no they bragged about this at the Surface presser that WinRT works with 420k devices.
I'm assuming that was directed at my comment, and yes I know that... (though if you total up the devices on the compatibility page it amounts to just over 40,500) But I digress... Just because WinRT might work when directly connected to a printer through USB doesn't mean that it will work if it's connected through a network connection. That's the point I was getting at.
Also, not all network setups or connections are equal. I'm sure printers are more likely to work when directly connected over a wireless network than they would if shared through another PC or print server. Having additional devices in between can add complexity and sometimes won't allow the computer to "see" or communicated with the printer correctly... hence one reason that it may not find the appropriate driver, even if one is supposed to exist.
Also, just because Microsoft says something is compatible doesn't necessarily make it so... (unfortunately) For instance, they say that the Quadro NVS 110M GPU is compatible with Windows 8 but I haven't for the life of me been able to get it to work in either x64 or x86 environments on a Latitude D820. The website says it's compatible. When I ran the upgrade compatibility scanner from within Win7 x64 it said it was compatible. But when actually installing Win8 on the laptop, it won't install anything more than the generic Windows Driver. So the lists aren't always 100% accurate.