I would like to get a peak at the PayTrace api docs first, if you can get them, I couldn't get them without contacting a reseller or paytrace, not sure how long that would take.
I have not specifically written an ubercart mod, but I have written D6 mods, and I reviewed a couple of the uc payment modules to get a feel for the flow and callbacks, I think it would be straightfoward to use them as a go-by and create this module, depending on the complexity of the paytrace apis.
Send me a private message if you would like to discuss further.
Brian
