chorkman on 8/1/2008 at 20:51
If you have the Deepscorn Hollow expansion, a new merchant Rowley Eardwulf will appear in the Wawnet Inn, in Weye, just west of the Imperial City. He has 2000G and will buy weapons and armor. I imagine this probably holds true for the other 'fortress' expansions as well, as each would need a new merchant to sell the upgrades for its fortress.
Peanuckle on 14/1/2008 at 00:10
I read up on the oblivion wiki and found out that by maxing out mercantile and I think it was speechcraft, that you could add 1000 to the gold total of the merchants. There are also various mods that alter their available gold based on what you buy/sell. One even gives their gold a variable, so that when you buy, they have more and when you sell, they have less.