The Victoria 2 Realism & Rebalance Project
Realism and game functionality are compatible until proven otherwise 
The following is by no means an exhaustive description of what VRRP does, but should give an overview of its general state and planned future.
The Victoria 2 Realism & Rebalance Project (VRRP) is an effort by the undersigned to rework Victoria 2 from the bottom up along realistic and consistent principles. The ultimate objective is to create a world which is completely dynamic and self-regulating to the extent that the world economy will always be able to reach a long-term equilibrium regardless of its current condition. Each aspect of the game interacts with the others to achieve that aim. Economic rebalancing is the original heart of VRRP, but over time, it has expanded to cover many more aspects of the game, and intends to expand further. VRRP is simulationist in outlook, avoiding arbitrary, unrealistic balance limitations. If something would not have been possible in real history, it should be impossible in VRRP too through proper simulation of the underlying causes that made it so, not via a hard rule saying you can't do so.
A few highlights of what VRRP has to offer:
-A productive economy reworked from the bottom up, starting from initial assumptions about profitability in market equilibrium
-An economy using a new line-up of goods, with supply-side substitution included by allowing for multiple, alternative ways of producing a certain final good
-An economic development paradigm where capital accumulation is the main inhibitor of factory growth, and profitability highly dependent on clerks and output tech, rather than getting craftsmen (which is easy for most countries, but only having craftsmen means you'll be producing cheap junk in bulk at low profit margins)
-A new tech system favouring economic specialization
-POP promotion/demotion mechanics designed to make the ratio of different poptypes be in a condition-dependent dynamic equilibrium, where poor pops tend to drift towards the best-paying poor POP job, while the ratio of middle POPs to poor POPs depends on literacy and slider spending
-Completely reworked migration mechanics so that economic factors are the main drivers of migration - poverty and unemployment pushes people to move, high living standards pulls those immigrants in, and consequently imbalances in the world market are smoothed out as people abandon overproducing RGOs and move into ones whose goods are in high demand
-A semi-invisible, event-driven regulatory system ensuring that the size of the global money supply keeps pace with the productive capacity of the world, making sure that money is scarce enough to remain relevant but abundant enough to keep the world market from croaking due to universal lack of demand
More info to come, including a manual. Version 2.0 just got released, be patient...
Hall of Fame
Editor-in-Chief
Konrad Richtmark

Team Members
People who commit to taking care of a particular part of the game, or otherwise made consistent contribution to it.
Phi - Minister of Demographics and Migration
Modular Contributors
People whose mods or specific fixes have been integrated into the Project
Xcapos - CanalMod
Keder - Intelligentsia Tiny Mod
Shauf - Rebel & Reform Tweak
mate0815 - German translations
adj_boy - Aesthetics rework
zenjr - Brazilian RGO setup
TekcoR - World Fairs Mod (incorporated by Phi)
Trovador - New Nations Mod (partly incorporated into VRRP)
JoneshSwe - union tag event/decision carryover, and help with incorporating NNM
GAGA Extrem - lots of political events, and reworked election events
Gabryel Karolin - most of the new goods icons
Honourable Playtesters
Players whose feedback has been invaluable for development
mike8472
Stonewall
DoctorPlague
von Sachsen
wertu234
Innocent Beard
Other Honourable Mentions
People who have significantly contributed in other ways
way2co0l - for writing the original POP promotion & ideology scripts
Naselus - inter-mod R&D efforts, and many things filched from PDM
Xcapos & Masakary - for answering a bugslaying call to arms

Andrelvis - intrepid brainstorming
seattle - writAAR
Kinniken - for his POP editor tools
SashaM - intrepid experimenter
FAQ
I have this great idea of what the mod would need, and would like to help! Can I join the team?
-Well, tell us about your idea. The modus operandi is to allocate each team member responsibility over a specific part of the game, as you can see in the team member list. For each aspect, we agree together on a general design philosophy, ideas, goals and outline. Then, the team member responsible for that part has operational freedom to realize those goals as s/he sees fit. If you have a vision regarding a part of the game yet untouched by VRRP, tell it to us. If your vision matches ours, and we can come to an agreement on a general outline as described above, you're welcome aboard. If you have a vision regarding some part of the game that already has been thoroughly reworked by VRRP, however, the situation becomes more complicated and will have to be considered on a case-to-case basis. In any case, drop us a line.
I know of, or have made myself, an awesome mod that I think VRRP would benefit from integrating. Would you consider it?
-We're certainly open to that, and have already integrated a few, as you can see in the Hall of Fame. Feel free to suggest it. The most important issue is whether we think the mod fits within the stated design goals of the mod. Changes that are both potentially controversial and clearly beyond the stated goals will be avoided. And speaking of changes, a final thing worth mentioning on this issue is that we might have to make slight changes to the mod in question simply to make it work in synch with the rest of VRRP. But regardless of whether we do, the authors of the original work will be credited fully in the Hall of Fame.
Can I integrate VRRP or part of it into my mod?
-Yes, certainly, as long as our work is acknowledged, preferably via a link to this post.
CURRENT VERSION
DOWNLOAD VRRP v2.01
The current version is 2.01, installed by extracting the compressed archive into the mod/ folder under the main Victoria 2 folder. When running the game via the launcher, a tickbox should appear for VRRP in the lower-left window.
Correct checksum is TXUZ, together with A House Divided, patch 2.31