These have been selling really well:
New Frontier 80% Glock Lowers. They will use an NFA 80% JIG. Assuming one takes normal precautions when using the jig, it should be able to be used multiple times.
FWIW, we should be seeing Spartan9 100% 9MM Glock Lowers incoming soon. They'll retail for approx $149.95 fully machined and anodized.
Are you planning to carry the 100% NFA 9mm lower as well?