Not sure if you're still watching this subject or not, but if you are:
If you don't want to use the checking acct or credit card, Western Union fees aren't exactly minimal, but it's essentially a money order and quite a few places take it. 900pay is another option if you can call 900 numbers from your phone. The limits tend to be pretty low, and not sure if many places take it, but it gets tacked on to your phone bill.
Here's what I found opening some of the rooms I have installed:
Accept Money Order:
bet365 ("regular mail deposit" an international money order)
Accept Western Union: