Whether OfficeMax has any of these left or not is questionable, but like I said, I got a Cendyne 48x12x48 on Sunday, and I'm sure that they were out of stock by the end of the day. You might luck out at your local store, however, and there is always the chance that more may be shipped in. I noticed that there is no disclaimer in the ad, so you may be able to score a raincheck.
I actually opened mine up today to send in the rebate and noticed that my CD/RW is actually a Samsung 48x24x48 drive (at least that's what's printed on the bezel). I'll be plugging it in later tonight and try it out...
Good luck to the rest of you!