ASGT that means advance series mount are made by Celestron we here call it CG-5, the meade counterpart should be the LXD-75 Gem Mount. I think right now celestron have the upper hand on the GEM mount market than meade (with their all star polar aligment). Both mounts are aproximate for 35 lbs visual use..and at most 20 lbs for AP.

Here si the link for the Celestron One:
http://www.celestron.com/c3/product.php?CatID=16&ProdID=92

Arthur i think you can make the L shape or on some telescope shops they sell the adapter for the vixen style plate.

I think if you want real AP the go to GEM mount is the way to go! and maybe you can buy a SE celestron mount for the grab and go...i think meade too sells alone the DS-2000 mount alone (its alt?azm go to mount sell with DS-2000 telecopes) but i dont know if it can carry the ETX-125 OTA ..maybe you can ask around.