Gift certificates currently have a draconian "verified by visa" option as the ONLY way to complete a gift certificate purchase. This requirement makes it hard to get people to give gift certificates - my wife tried to surprise me once with a newegg gift certificate and I had to end up helping her register the stupid verified by visa program and complete the order! Some surprise it was when I had to step her through the entire process, and she was so frustrated that she will buy a gift certificate from you again.
I understand you're concerned about fraud, but can't you find a better way to allow people to buy gifts using your site? Why not just use the same fraud-prevention methods you use for standard retail sales? It doesn't matter if it takes a day or two to issue the gift certificate, as long as buying one is as easy as buying anything else on your site.