Totalmix would then need to run these VST's on its FPGA, and while they are getting more powerful, I doubt it could run a few x86 VST's in any type of emulation mode and have any power leftover for anything else. Or, you would still need a native "host" x86 compliment to Totalmix's internal processing, and you are back to using ASIO to get to/from the Kernel to Totalmix (and the physical I/O)...
I'd have to assume the new TM-FX DSP is succinctly coded "natively" to run on the FPGA (not ported from x86 code or running in emulation) - and were likely designed from day one to be as efficient as possible. VST/RTAS on the other hand, has access to an i7's worth of DSP (that is a LOT of power!), so the coding is generally more sloppy and less optimized/tight...
Use a fast PC, use low-latency plug-ins in a descent host, and run your ASIO driver as low as possible. You will have all of this and more. That is my M.O. 24/7/365 (or 24/7/366 for our Leap Day coming up tomorrow!!! )
MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8