Smart package deal

Hi there.

I have been looking for a extension that could do the following:

A extension that lets customers pick f.x. 10 different products (lets say posters) for a specific price. But not just any products on the site. Only the ones in a specific category f.x.
And i do not mean just 10 products but the customer decides them selfs which product they want. They could select f.x. any 10 posters out of 50 posters and get it for a certain price.
To sum up: a x amount for y price extension

Is there any extension that lets me do this ?

regards
Reprohuset