To your first point. I am looping the output from an already recorded dry guitar track in Sonar through hardware and then back into Sonar. Reamping might be new to some folk - it means sending a recorded guitar signal to (for example) an amplifier and then processing that signal with effects, eq, etc before sending it back to be recorded.
However the crux of the matter is you simply cant do this with what is essentially a wav file. The signal needs to be converted to a HI Z level so that the amp can recognise it. Its basically the opposite of DI ing.
To add to this what I want to do is listen to my whole project while I am processing the signal so that I get get a perfect sound before actually recording it.