Searching for module for selling products at a per square foot basis

Hi All!

I'm new to this forum so I'm not sure my question belongs here but here it goes...

I need to know if anyone has ever come across a module for selling products at a per square foot basis. I just installed Zen Cart at http://mountvernonbanners.com and I am still in the baby stages of putting the whole store together.

I sell printed banners and the pricing would be way easier for the customer and for myself if I could offer a printed banner for say $XXX per square foot.

Hope someone can point me in the right direction, in the meantime, I'll keep on searching and update this post if I come across something good.

There's no mod I'm aware of. Search the forums for "square foot" for a few threads that deal with this.