You talk about these server-side webkit parsers as tricks that “slow things down,” which indicates that you at least ultimately got them working. I never got that far.
This isn't always appropriate of course, those apps aren't really relying on data from a database, they're proper SPAs. But as noted by others, there are ways to fool crawlers if it's something you want to do.
Generally though, the feeling is that crawlers not executing JS is going to end, and the problem will go away on its own.
You can do that, however if you dump static page to Google bot IP only it's an SEO cheating.