In the old stargate mod there is talk about ring transporters and asgard beams. I bet you have most of this down already but have you thought about getting in touch with the author of the transporter mod to modify it for an asgard beam to save yourself a little effort? Then it could mostly come down to changing graphics (still a big deal, maybe the biggest part but still less work overall)

I was also wondering about adding in the atlantis elevator/transporters as a means to transport to same-grid locations and maybe very close friendly grids.