Has anyone done any work to limit a GC usage to a set of products? I.e. instead of giving the list of products for free, to have that list (or a list from the get_gift_certificate_info hook) be a list of eligible products where the GC's usage is limited to that set and the GC amount is adjusted based on the price of the eligible products in the cart?
I.e. GC amount of $10.
Free products (or other list of products) has:
abc - ($2)
def - ($5)
hij - ($7)
1 -xyz (not in GC list, rice = $5)
2 - abc
Non-GC total would be: 5 + 4 = $9
After application of GC (only 'abc' is eligable for usage): $5
GC Balance is $6
Before I go do this work, thought I'd check to see if anyone's already done it an wants to sell the code. Seems this would be great added functionality to the GC addon in cs-cart.