Originally Posted by
well biked
You could try this to make the 10 speed shifters work with the nine speed cassette:
http://www.sheldonbrown.com/gloss_aa-l.html#alternate
But honestly, since this is a new build, if you go nine speed I'd get nine speed shifters to match the cassette. Or stick with ten speed since you've already got the shifters. As I said, the 10 speed chain might not even be a problem, maybe someone who's done something similar can say whether it will work okay with the cranks.
But wow, for the gearing you're after, it can be had for so much cheaper with nine speed parts.
I have tried the alternate cable routing. It worked but was very finicky, it'd probably be more so with a wide range cassette but you never really know till you try. The only sure bet is to use matching shifters and cassette.