650b Croix De Fer - Congratulations, it's an apple.

9 speed will give you more options I think. You can chop and change between mtb and road parts easily.

Or according to @danstuff try a 9 speed decore rear mech with 10 speed road kit:

As is 6700, and while both 6600 and 6700 (and any other 10 speed Shimano road shifters) will work with a 9 speed MTB mech, as the cable pull ratios are the same, neither will work with a 10 speed MTB mech, which has a different pull ratio.