TheEpicenter.com has them in a variety of fashions, and they seem to keep pretty much constantly in stock, atleast according to their website.
Also, I can say that, for the most part, the wonder of MREs has worn off, except for the pound cake, but its nice to keep them handy for disaster food and that sort of thing.
EDIT: Avoid the vegetarian omelet. Honestly, its called a Vomit Omelet for a reason. Its one of the more disgusting things I've ever eaten without modification, and that includes a fistful of tripe, but tobasco won't do anything for it. I highly recommend the ravioli.