People here seem to like some 'realistic' elements to the game...i can appreciate that too.
How about this.
do away with guild stores...hear me out.
now, each major town has its own 'trade house'. this functions exactly like an auction house, only they will NOT be linked. You place items in a city's trade house and it will only appear there, each city having its own place with differing items..again, faction specific.
here the idea suggests some level of realism in that items aren't viewed across a continent, you must now travel and look for items. puts the ideas of inventory into play