I had go at making a theme ages ago and used Dreamweaver, you can get a free addon that deals with all the mods and positions.

I didn’t spend much time on it other than that as I was trying to learn PHP so it has been left on hold for a bit.

But dreamweaver and the addon is an option (if you have dreamweaver)

** Just thought
There is a Joomla template generator software online somewhere, I remember seeing it. it might be worth a look in Google (sorry Yahoo).

Lol

Good Luck