IMHO its either PVR or Nvidia. The reasons are simple: Martox has just released their chip, ATI prototypes have been in Anand's and Epic's hand for some time already (more than enough comments show that they know how fast and how R300 is gonna behave in UT2003) and 3DLabs was not mentioned in this article (plus their preview boards have already been out for a little while too AFAIK). For Anand and Epic to be excited about getting to benchmarkt something "special" I think it's got to be new, inthe sense that neither of them has had a chance to see actual hardware of the product in action yet.
We haven't had much news about someone licensing PVR series 3 or 4 yet, but I have faith in them and I think it is possible someone could finally have quitly licensed and produced some higher end PVR tech - it'd most certainly be a very cool surprise!
Additionally to PVR, that leaves Nvidia with either nForce2 or NV30. NV28/18 or something else along those lines hardly counts, as it'd most likely behave 99% like a GF4Ti/MX, which isn't really worth calling it special. I also believe its very well possible that Nvidia has alpha boards of the NV30 ready by now (even in .13 micron - not being ready for mass production isn't the same as not being able to produce anything at all in the process AFAIK), similar to ATI having R300 alpha boards already over 2 months ago. I keep hearing how incredible late NV30 is supposed to be, but most of that noise is generated on forums and by the Inquirer, so I don't buy into NV30 being much more than maybe a month or two late.
Just my 2 cents ...