I broke down and bought a morgan carbtune this summer and it was great. It's a real nice tool, simple, good quality and I like the fact that it has no fluid, just metal rods that move. It isn't the cheapest way to go, I paid around $100, but it is real nice to use and I think it will last forever. It comes from England but shipping didn't take long, I had it in a week. It came with very good instructions too.
I also didn't want a great big contraption that I made myself, mainly for storage reasons. There's plenty of room in my toolbox for the carbtune. The only downside is that it's more expensive than a homemade thing, but I don't think you'd regret buying it.
Check it out:
http://www.carbtune.com/