I'm looking for the same thing. I want to use it for everyday partial commuting, but to be able to race it in the this autumn's season. I want it to be able to withstand being tossed in the back of my truck sans bike rack and with a cap, as well as daily commuting about 20 miles.
The research that I've done so far has netted me about 6 bikes:
-The Felt Breed as mentioned above.
-The Masi Speciale-cxss as mentioned above.
-Salsa Chili Con Crosso frame to be built up by LBS
-All-City Nature Boy.
-Surly Cross Check frame to be built up by LBS
-Bikes Direct Motobecane Fantom Cross Uno
I'm leaning toward the Masi or the All-City bike because of the ruggedness of steel, and the features on the bikes. The Masi is a little lighter with the carbon fork, but that might be a problem using it for everyday commuting. The All-City Nature-Boy has some interesting features and interesting dropouts, but is heavier and seems to have cheaper componentry than the Masi. I may have to flip for it. I'm also talking with a couple of LBSs in the area about the two bikes, or if they can find out any others that might fit the bill.
The Motobecane, although priced nicely, looks like you get what you pay for. On the interweb it looks much more cheaply made. I don't anticipate it looking better in real life. I'm not sure that I'd want to mail order it and then decide that I didn't want it once it came.
The Surly really isn't what I'm looking for in a single speed bike. I'm not interested in a SS with a derailleur dropout. Guys at one shop mentioned a Caad8 frame built up SS, but I nixed that for the same reason.
The Felt and the Salsa look like excellent bikes, but with using it for commuting, I worry about fatiguing the aluminum at various points. I would consider them for a CX specific bike, and If I decide that I like racing, then I might do just that. That said, I like the replaceable nature of the Salsa with the two different dropout possibilities. It makes the frame more versatile and would look good either way.
If anyone as more information about this or wants to debunk my thoughts on Aluminum frames or anything else, I'm open to the sell.