Yeah, okay. I didn't think I was crazy. I've just loaded 2.13 GB into the vsl-server (plugin), and 1.35 GB into the standalone. Three instruments - solo violin (standalone), viola, cello (plugin), all playing through my RME card, and all taking midi from my keyboard. So it does work, though I haven't tested it with wiring audio/midi through Logic. I'm running the plugs in Bidule.
For some reason when I launch the standalone it resets my sampling rate (Audio/MIDI setup) to 96 KHz... weird. That was obviously the problem I was having before.
In my case, I've only got 4 GB of RAM, so with 3.57 GB "wired" my system gets somewhat useless, but the standalone + plugin idea does work.

http://www.rubato-music.com/Media/images/server_2.13+VI_app_1.37.png">
J.