App in review for 52 days — any way to escalate?

I’m an independent developer and my app, TalkCity (version 1.0.3, build 23648159), has been in review for an unusually long time:

September 1 — first submission
September 7 — resubmission
September 25 — resubmission
October 1 — latest resubmission
October 23 — still “In Review”

That’s 52 days since the first submission and 22 days since the latest one, with no decision.

I’ve contacted Developer Support several times. My expedited review request was accepted, and Apple confirmed the app is still under review, but no timeline or further information was given.

I’m not asking for automatic approval, just a decision. If something needs to be fixed, I’ll fix it right away. If the review needs more time, any indication of why would help me plan the launch.

To other developers:

Has anyone had a review take this long?
Has anyone had an expedited request accepted without visible progress?
Is there an effective way to escalate beyond the standard support replies?

Thanks in advance for any advice.