I am thinking about throwing some flat bars on a cross bike for riding local trail trails with the wife. It's got a 9 sp 11-25 cassette, 105 short cage RD and a Tiagra FD. I know that using trigger shifters with the FD may be problematic. I was looking for a decent set of Deore shifters on e-bay. Anything I should look out for? Any 9 sp Shimano shifters that won't work? I don't want to buy a bunch of stuff only to find out it won't be compatible.
... or, I could throw on a 10 sp cassette and use SLX or XT 10 sp triggers? I've got a 105 10 sp cassette laying around and that might end up being easier.