Expectations for warranty repair timing

I would say that some of it depends on the country of manufacturing. If the company is in the same country as you, I agree, that a month should be plenty of time to provide most common services.

However, if you are dealing with International shipping, and/or extensive damage repairs, I could certainly understand it taking longer than a month.

In my experience, one must temper impatient desire for the return of one's gear with a realistic appraisal of the manufacturer's size and scale of operation. If you have a component from a one or two man shop, a month's wait is nothing unusual. I've had an amp sit waiting for repair for multiple month's from one well known but small manufacturer. On the other hand, if I had gear go back to someone like Bryston who operates on a larger scale, I would expect a repair to be completed within a month's time unless there was a delay for parts. However, I've also heard more than one person complain that really large manufacturers can be really slow and unresponsive as well. In any event, I learned long ago, have two of everything so you've always got a backup. 

Thanks.  This isn't extensive damage, but the manufacturer appears to be having trouble fixing the problem (though they've clearly been able to replicate it).  Question is, when should they offer a replacement unit or refund if they can't get it repaired?  

That month doesn't include shipping.  It's been back with the manufacturer for a full month.