According to a note published today at MSFN, Microsoft finalized the beta stage for Windows 7 and is currently working in the Release Candidate 1. According to the same note we could probably see the RC1 released as soon as February 27.
The build string is indeed "7048.winmain_win7rc1.090211-1625," and it tells us much more than just than the fact that it was compiled on February 11, at 4:25PM (a week ago). What makes this build significant is not only that it's the first build (that we know of) compiled in February, or that it's the first 704x build we can confirm, but the inclusion of "rc1" in the string. This suggests that Microsoft has finished with beta builds and is now working on the RC1 branch builds.
I really don’t know up to what point all this is real but I can say that Microsoft has been working in W7 with a speed that I never have seen before. So it would not surprise me at all if we begin March testing the RC1 and have by the end of June the RTM released.