At *some* point backward compatibility will be broken. The core devs have opted to do one release that will break a lot of stuff, rather than several releases that break a bit of stuff.
If you don't want to hack the code to remove tables, and you don't want to wait for the WCAG release, then, I suggest you find another CMS. I don't say that in jest. You're not leaving us much choice here.
I assume you've seen this:
http://forum.joomla.org/index.php/topic,24921.0.htmlYou can still create your own tableless template, and once the accessible package comes out with 1.1, you'll be much closer to your goal.