EJ kinda did this for a little while. If I remember right, he was mic’ing his Twins with a small JBL PA, running the tape echo through the mixer’s send/return and then mic’ing the PA speakers for his wet signal.
I think the only issue you’d run into is that what’s going to come out of the PA speakers is going just be the pre-amp with effects if you’re setting it up the traditional way. It might be a little shrill since it‘s not guitar speakers, but I bet the cleans will sound fuckin’ ace!