There are some fine floor mounted fx units available, I like the looks and specs of these two:
($1500 or so, but no amp simulation, doh!)
and the much cheaper
($500 or so)
However, I don't think these serve your current and future needs.
Also, I must admit that I haven't played either one. I have a Digitech GSP2101, which, at the time (1990-1991) was one of the top units.
It still rocks after 15 years. In fact Digitech are still selling the Quad4 studio fx, which is just a slightly updated version of the fx section of the GSP2101.
Digitech currently offer similar technology in floor units like these:
I would not go for a floor mounted system, I would again go for a rack mounted unit, with a separate foot controller. But for your needs it may be a good solution.
The only truly new developments since 1990, have been the whole modelling thing and computer I/O. I haven't been impressed by the tones from most of the units using the former, the latter appears mandatory for you. I've tried Line6 units and I didn't like them at all. With a lot of tweaking, some people have found decent tones in there.
Top of the line in modelling is probably Boss with their COSM series. They have just launched a new top machine which exactly matches your needs, the GT-Pro:
It looks like good value for money ($845 without foot-controller, though) in fact it is cheaper than my GSP2101 was back in the days.
Another unit I would definitely check out is the Rocktron Prophesy
It kinda looks like the GT-Pro, performs many of the same functions.
Both of these are about twice as expensive as the PODXT Live, but well worth it. The Variax 700 seems way overpriced ($1400!?), for that kind of money you can get yourself a decent Ibanez! The V700 doesn't strike me as high tech either. How about a nice IBANEZ RGA121VLF, RG1820X or SZ720FMTG? That way, if someone invites you over for a low-tech jam session, where amps and stuff are provided for, you can just show up with a proper guitar with built-in proper tone.
Final note, I've always felt that you should spend about equal amounts on guitar, amp and effect. For both the Boss and Rocktron, I feel that in you are still missing something when you don't have a proper power-amp and cabinet or combo. When spending $800-1000 on a guitar and the same on an effects unit, you may also want to consider a nice $900 2x12 combo. The perfrect companion to either GT-Pro or Prophesy would be a Boss JC120 or Fender Twin Reverb.