Just thought I should give u guys a heads up on the XTX to XTR question since many people state that its not possible to mount a 21" front wheel in the XTX fork.

Im glad to tell you that your wrong! Its absolutly possible, and simpel too.

I just completed my conversion and the bike is now ready for the offroad.

What you need from the XTR is of course the wheels, but also the front brake caliper, front brake disk and front wheelaxel spacers.
Rear wheel will fit "bolt-on", but for the front you need to manifacture a adapterplate to the XTR caliper and also modify one of the wheelaxel spacers to be able to center the wheel in the fork.

But other then that it will fit really easy.