Super Rewards of OfferPal intergration?

I was wondering if anyone has written a payment plugin for the following virtual currency type payment systems.

http://www.offerpalmedia.com/

or

http://www.srpoints.com

These have simple api's with a post callback system, can do json or xml data as well.

If nobody has written one but has written other modules can you write up what might be involved in hooking into this with drupal?