Well, this is certainly unexpected.
After sending in my bad stick of ram, Wintec tested it and said that it seems fine. So they've requested that I send them another stick of memory so they can replace the pair with a new matched pair (they're covering the shipping for the second stick).
I was a bit annoyed that I'd have to either use 2Gb of memory or settle for the 2x2Gb G.Skill DDR2-800 I had laying around if I wanted to game. This would have knocked a good 600Mhz off my clock speed since I'm not a fan of overclocking memory beyond its spec.
But just for kicks I decided to just throw the G.Skill memory in my system with the same 942Mhz bus speed set. I loosened the timings a bit to increase stability, but that may not have even been necessary. Its perfectly stable! Even with the Wintec memory in there as well, for a total of 6Gb it ran memtest for a half hour and the system has operated without a hitch for 3 hours now.
So... I had a bad stick of ram and now I've got 6Gb of RAM without effecting my overclock. This is totally unexpected but I'm really happy to have a little extra memory to let Windows 7 stretch its legs a bit more.
Today was a good day.