I think one thing you have to keep in mind is that you can't please everyone. It sounds like you're trying your very hardest to make sure every customer is satisifed (and that's great - I have a lot of respect for you, just from what posts I've read of yours on the forum so far), but in the end, there's always going to be at least one person who cannot see from your point of view. People are irrational, flawed and, essentially, human. You can't please them all, so don't kill yourself trying to.
The easiest and possibly best solution to me sounds like just cutting out backorders all together for international customers.
Anyways, it looks like you've got a million opinions here, so I don't want to add too much to them. Just wanted to cheer you on and say keep up the good work and don't let this get ya down!