Tero

I like the idea of a "stamp" type controller. One suggestion, I would think of a different name before bringing it to market, I think "stamp" may be trademarked.

Also realize that by making a "kit" type controller will open you to a flood of technical support inquiries. "I bought your control card and made a crappy bridge circuit, why won't it work?" Things like that I would think will be fairly common. You may want to specify what type of support is available for this type of product. Ie. You will help with control/interface problems, you won't help diagnose power stage problems. You can get into a situation where people talk bad about your product because they can't make it work with their amateur power stage. Tread carefully.

Keep up the great work
Matt