You might want to post your questions in the Team Metal thread.
I don't have any experience with some of the things you posted, so I can't really say much that would be useful about them.
I will say that I have recorded several metal shows with a Roland R-05, though always with external mics and a battery box or preamp. I haven't had any problems with the R-05, so I'm not sure what you mean about it not being able to handle a hot signal.
One thing that's not clear to me is what, if anything, is wrong with your H4n? You said it has a lot of features you don't need...but is that really an issue worth buying a different recorder over? Unless there's something wrong with your H4n, it doesn't seem like a wise use of your budget to buy a different recorder