Most suppliers aren't set up for that except through pay services like Alertpay. Plus it leaves a paper trail directly to you.
No supplier worth using will take credit cards. Most take E-currency though which you can buy from an exchanger with a credit card, although that is really not a good idea. Better to buy ecurrency from an exchanger with like a money order or cash.
But lets say I don't have this paper trail and my name isn't attached to it. I only have 2 sources one is a Nintendo Ds Researcher and another is from the maple leaf country. Both of them say to contact for payment, whats the best way to set some kind of account up so I can pay them what they want, ecurrency or whatever they would likely accept...
The best way to pay anyone really is with E-currency no matter what they take (besides CIM). The most popular payment methods vendors take are: E-currency (Liberty reserve, Pecunix, etc) Western Union and Money Gram You can set up an E-currency account, fund it by buying from an exchanger who accepts credit cards (make sure you don't get scammed a lot of e-currency vendors are scammers but a lot are legit also do research) and then have them fund your account. Once the E-currency is loaded on your account you can either just transfer it to the account #s of the people you owe money to if they take ecurrency, or if they only take WU or MG you can cash out the ecurrency to an exchanger and provide the details that the person you owe money to gives you (that way you are not on camera at the WU place or leaving a paper trail in your name). I personally wouldn't use a credit card to buy ecurrency with though why bother when they take fairly anonymous ways of payment themselves.