You can also just tinker by hand w/o the expense and delay of learning a new cad approach. Just get a three-view of what you want, blow up to the size you want and start pencilling in piece locations. If you've built a kit, you already know the general location and structure of components.
What is a desk sized profile? Is it like the DJ Aerotech Roadkill electrics? Check them out:
http://www.djaerotech.com/
Good luck,