I just came across this, so apologies for the late reply.

Generals can be recruited through buildings if you mod a bit. This involves unpacking the files (which takes up about 5 Gb of disk space, and is a bit of a fiddle).

The topic is covered on the .com FAQ, Q 36, at:
http://forums.totalwar.com/showthrea...me-Fixes/page3

For your entertainment I have copied and pasted the entry here:

Question #36: How do I recruit generals?

Answer #36: It is very easy to mod the game so that you can recruit generals. Just add this to your export_descr_buildings.txt file:

recruit_pool "Mongol Bodyguard" 1 0.2 1 0 requires factions { mongols, timurids, }
recruit_pool "ME Bodyguard" 1 0.2 1 0 requires factions { moors, egypt, turks, }
recruit_pool "Greek Bodyguard" 1 0.2 1 0 requires factions { byzantium, }
recruit_pool "EE Bodyguard" 1 0.2 1 0 requires factions { russia, }
recruit_pool "SE Bodyguard" 1 0.2 1 0 requires factions { spain, portugal, milan, venice, sicily, }
recruit_pool "NE Bodyguard" 1 0.2 1 0 requires factions { england, scotland, france, hre, denmark, poland, hungary, }

You'll need to do this for each building which you want to allow the creation of general's units.