I can now say there is a good chance you'll see it soon. I first had to fix the build system to work on 64-bit boxes. This may seem like an odd prerequisite, but I don't really have space on my 32-bit native box for yet another version of visual studio, so I had to get things working on my 64-bit Win7 machine. Visual Studio is 32-bit and runs in the Wow6432 compatibility layer, so there were some tricky things (watch out if you run scripts from inside a build process: the batch file used to launch MSBuild or Visual Studio is 64-bit, but the batch files launched by those processes are 32-bit. The Visual Studio registry keys are in different places for each bitness).
I've now installed VS2012 and the SDK, gotten the preliminary development tools to compile, and gotten the main package to compile and install. Getting VS2012 to recognize the extension was harder than VS2010 and there were a couple of other initial problems (no colorization in the fact editor, error activation isn't selecting specific items in the properties window). I haven't tried to build any other components yet (code generation, relational extensions, setup, etc). However, for a first pass it looks very promising, certainly much easier than the jump to VS2010.
I can't give you a firm date yet, but the initial indication is that I can put it in the next public release with the current feature set. I won't be able to look at Win8/touch/metro features until later in the year.