Hmm, that would be interesting. Only problem is that the original WebTV/MSNTV was an in-house set-top box with a proprietary OS (which runs on a 64-bit MIPS CPU). Unless someone could hack the ROM to make it connect to a different server and flash it back on the WebTV (WebTV’s OS is stored on nonvolatile memory), we can only dream.
As for the MSNTV2, it’s basically a glorified Windows CE device, so we’ll have to see what we can do with that.