I would certainly pay some heed to Clark's comments. I have my doubts that there will be a SRD near 4e launch time, and likely not early for publishers at all. I still have my series of RTFs from the 3.0 PHB that was sent out by Ryan Dancey, wonking formatting and all.
In fact, I would much prefer a laundry list style documents of what is and isn't open because it is much faster for WotC to do, which makes it more likely they will keep it up to date. The only significant amount of time would be the decision process, then give someone an hour to make a list to post. Much faster than the weeks of retyping.
However, that being said, there's a chance 4e will work differently than 3e. This time around R&D isn't typing into Word documents that then need cut and pasting and/or retyping to format different. At least for all of the rules work, they are using a database to enter it all in, so that the D&D Insider generators has all of the content already in there. So it sounds like they are using the database to spit out the content for the books as well. If so, then it's a small step to use that same database to spit out the SRD. If they set it up right (and if they did it early on, it should be easy to set it up that way), then updating the SRD is still as easy as the laundry list. Just rather than typing a laundry list, they just click a button for each item on the list.
I have no idea if they have considered that or not. I would hope so since it would be closer to a trivial amount of time to incorporate something like that from the beginning. But it wouldn't be outrageous to build something like that later (but the "not trivial" amount of time might be higher than their threshold to devote to it).
Either way, the presence of the content in a database format at WotC does change the equation for 4e and could cut down on a lot of the re-typing issue that was probably the largest hurdle in keeping the SRD updated (from WotC comments it sounded like there were more approved changes, just no time to push them out in an approved way). Like Clark, I'd just love it if WotC found the process that works for them that allows them to potentially release open content from any book with the least amount of effort on their part. If that's no retyped SRD and just a RPGA-style laundry list of what's allowed. That's fine with me since the entire purpose of the SRD is for publishers (and whether or not WotC posts full SRD documents doesn't matter since someone else eventually will).