Sorry, I've not had that problem, but I do live in a not so hot market, though houses are selling faster than ever. I heard appraisals were taking a long time, but I had one done the end of March (pricing our house to sell FSBO) and it was about 5 days before the appraiser came to look and then a few more to get the report. We just sold our house (the same one the first appraisal was for) this past week, and the buyer had their appraisal complete within two weeks of a signed offer. I don't know when it was ordered, so it might have taken less time than that.
When I was showing the house, a common thing mentioned among the real estate agents is that they all recommended using a local lender. They said the process goes through much smoother, with less hiccups due to wonky appraisals or other issues.
How far along are you with the bank? Is it too late to switch to a local lender? If you're using an agent, did they have any particular recommendation? When is the closing scheduled for?