I did once in the past. I had an issue selling Bitcoins on Ebay (go figure, right?) and was talking with their dispute/customer service and the guy eventually got my money back. He said I should just stop selling "intangible" things on ebay since it's a nightmare for them. So I asked him how Ebay plans to cover sellers considering there is a rapidly growing online market for games, media, and all sorts of other intangible items. They're missing out on a lot of Ebay/Paypal fees if they tell sellers to stop. He just kinda mumbled off saying that they are working for a solution for it. But yeah, everytime I get a chance to talk to them, I'll mention it.
Isn't that kinda like calling up Visa and telling them you want to be able to use your MasterCard on their network?