Kahn - perhaps consider putting on a Shimano XT derailleur? Those can easily handle a 30-34t. I've run my older 105 Short Cage with a 28t and there was very little clearance between the cog and the derailleur wheels. Not sure if I'd go to a 30t myself, but Bob seems to have made it work. Of course - YMMV depending on the dropout and hanger design of your bike.