I doubt they'll "risk" selling a laptop without an ODD. It's not like I don't like the idea: I do. The superdrive doesn't read Blu-Ray anyway, and there are some nice readers at a reasonable price already. Furthermore, it'd give them the option for iX + dedicated GPU, without the extra size and weight of a Sony Vaio Z.
Now my reasons: Most laptops have ODDs and it may be regarded publicly as a "fail" on Apple's part not to include it. While I don't agree with this, the general public would hardly understand what's at stake here, performance-wise. Also, I don't see them distributing OS X on a SD Card.
To finish, Sandy Bridge's article on Anandtech.com mentioned Sandy Bridge's price will be quite attractive. I do not like the idea of an Intel IGP (even with its promising early results), but the cheaper price also might counter your idea of non-ODD-laptops being more profiteable. Thus, I think the ODD will be present for some more releases.
Lightpeak will be out only in 2012, and USB 3.0 won't be a standard with Sandy Bridge. Unfortunately, I believe the chances of seeing these new ports will be small in the next release.
I kind of doubt #3. The Unibody model is the result of a severe and detailed optimization process. In addition, it seems Apple's "tradition" of refresh consist on longer periods of time.
I am hoping for #2, to be honest. Either that, or Sandy Bridge in case it does correspond to Anandtech's article (and ONLY if it does). It'd be a reasonable CPU update (C2D to i3/i5), and a minor GPU update: in the article, it scores above ATI 5450, a graphics card that is below the 320M; however, considering it was running at lower MHz and with beta drivers, the general idea is that it'd be superior to the NVIDIA 320M.
Hey, it's not like I thought it was a big update. Apple tends to alternate between Big and Minor updates, and according to that tradition, that one would have been a "Big" one (and C2D to iX on the 15'' and 17''s can be considered big, to be honest). But if you read my post attentively, you'll see I actually equationed the possibility of the 13'' update having been actually a small one.