Multi-store sharing a cart

Is there a way to link the cart, and wishlist, of a multi-store store? I saw one user offering a sort of service, but at 120 pounds...which is a lot.

For anyone that doesn't know, let me explain:
If you have a store on sub-domain 1, and 2, their carts aren't shared at all. This should allow you to show products from sub-domain 1 in sub-domain 2's cart/wishlist, and vice versa.

On a similar note, does the search function work for searching all stores, 1 store, or can you set up a system to look at store 1,2 or both?

120 pounds sounds like it's worth the money. Seems like a little bit of work to me