KS- allow me to illuminate your misperception. ALL Shimano MTB and road shifters that use conventional methodology (e.g. low rise RD, bottom pull FD intended for indexing) are compatible up thru 9 speed. Once we get to 10 speed you have to use the 9 speed MTB stuff with the road 10 speed stuff, but it qorks fine. Even works cross-speeds, so a 6-7-8-9 speed FD or RD will work fine with 10 speed crankset if you use a 10 speed chain. Only exception is DA 740X, and there are even some workarounds for them.

So, if you want to use a 7 speed Deore FD with a 9 Speed XT RD and a 10 speed crankset to run a 10 speed triple, it will work. Easier with down tube shifters and friction FD, but it will be OK with STI's or thumbies as well.