I would like to get an Alu-rack from SW-MOTECH, but it doesn't look like they sell 'em for the 620.  Of course, that could just be my failure to find info on the Twisted Throttle or SW-MOTECH websites (they're both pretty horrible).

Is anyone running this case on their Monster, and if so, how did you mount it?  I don't want panniers too, just the topcase.

You can put a Givi case on a Ventura rack.  I ran this setup until I found an original DP (Nonfango) top case and mounts...but good luck finding another one of those.

Here's a DP/Nonfango mount for sale:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200397320455&ssPageName=ADME:B:SS:US:1123

You can mount a Nonfango box on this, but not a Givi box.