I'd planning on purchasing wholesale and I only want to verify (NOT redeem) the cards, and I'd like to make sure they haven't been used or activated.

Is it possible to try this?

bump

Not that I know of. Using xbox.com it will automatically redeem the code. If you use them on xbox live, it'll give you the option to redeem or cancel. Obviously using the xbox method sucks but its the only option I know of.

Anyone have another idea? Your way works sonic, but like you said it'd take forever

There is no other way that I know of. When I need to check if a code is working without using it, then I plug a USB keyboard into my Xbox and test it. Takes just as little amount of time as it would on my PC.