David

You all might want to check out our work at www.vsd.bz. We have already built (and patented) the system that David G descibes. For a mind-blowing hmd, try www.sensics.com. Emagin also had a very nice and affordable hmd that works with standard gaming systems - www.emagin.com. The VirtuSphere is still under development, so don't sell it short...

It would be nice to have continuity between worlds. A transporter model would work but doesn't have the continuity. A doorway model would work, with a common symbol for a portal door plus destination. Another model is a variation on the LOTR-inspired "One World" concept, whereby there exists a portal world that one returns to or passes through one the way to and forth.