Ancestry said at Rootstech (in June? and repeated recently at another conference) that they have *NO* plans to release a chromosome browser. They know we want it, but they don't feel like it's the way to go.
Instead they are "working on something better" - but they haven't said what, and they haven't said when. (Only that it's not a chromosome browser. Argh.)
I don't have links, but I think this was recently reiterated on either CeCe Moore or Judy Russell's blog:
http://www.yourgeneticgenealogist.com/ and
http://www.thelegalgenealogist.com/ respectively