Surly Disc Trucker with STI Shifters I like the feel of Surly's Disc Trucker, 3x10.

http://surlybikes.com/bikes/disc_trucker/bike_specs

But I want STI shifters, not bar-ends.  Moving to STI would seem to screw up the brake pull; duly noted.

Two questions:


Will STI shifters work with the front derailleur?  (Sora Triple)
Will STI shifters work with the rear derailleur?  (XT 10-speed)


Guessing yes (front) and not at all (rear).  

It looks like a 9-speed XT RD would work and give me all ten in the back??
If you get a 3 x 10 STI shifter, the front (Sora) shifter will work fine. For the rear, you're going to need to replace it with a 10 speed Shimano road rear derailleur or a 7-9 speed Shimano rear derailleur due to the change in cable pull (7-9 speed and 10 speed road use the same cable pull in Shimano. 10 speed mountain does something else). Note that the bar ends spec'd on the Disc Trucker are Microshift BS-M10, which are specifically designed for 10 speed mountain cable pull. You can use the JTek Shiftmate 6 as an alternative to putting a 7-9 speed or 10 speed Road Shimano rear derailleur, but I'd recommend against it since its one more place the cable can be damaged, and it will cost more than buying a 9 speed Deore rear derailleur (which is what I'd do to save some cash rather than buying the 9 speed XT, unless you have it laying around or can get it for very cheap). 

As for brakes, the Tektro RL520's are for linear pull (V-brakes / mountain disc brakes). This means that the Disc Trucker is outfitted with the Avid BB7 Mountain disc brake calipers. So, if you want to switch to STI brakes, you can either swap out the brake calipers for road brake calipers (e.g. Avid BB7 Road) or use a Travel Agent, which is a pulley that switches the cable pull between short and long pull brakes. These increase cable wear at the pulley so you have to check them every so often to see the cable is in good condition. Travel agents may be a bit cheaper (two of them should run about 50 USD), but I'd probably opt for the new calipers since it removes one failure point in your brake system (two brakes with rotors will probably run about 100 USD; less if you can find them without rotors). Hayes and Tektro/TRP make disc brakes with short pull (such as the Hayes Comp CX) which you can also use.