Did you consider any of the Lifespan Fitness models? They sell complete kits, some for less money than the cost of what you built yourself:

http://www.lifespanfitness.com/tr800-dt5-treadmill-desk.html... http://www.lifespanfitness.com/treadmill-desk/tr1200-dt5-tre... http://www.lifespanfitness.com/treadmill-desk/tr5000-dt5-tre...

I have the mid-tier model and absolutely love it. Curious if there was anything in particular about it that turned you off (you obviously researched this project thoroughly).