I've added in 79 hidden events which give you retinue boosts based on the number of realm holdings you have. You no longer get retinue boosts from technology or buildings, but if you have the Imperial Administration law you'll get a +20% tax modifier and +12,000 to your retinue cap for every 50 realm holdings you have, starting at 50. In 769, Constantine V gets a +20% tax modifier and +48,000 to his retinue cap, which is the equivalent of 18,000 troops. The modifier scales up to 1,150 realm holdings, which will net you the usual +20% tax boosts and +244,000 towards your retinue cap (The equivalent of 150,000 men).