lucy24 - 10:53 pm on Sep 2, 2013 (gmt 0)
1) there are several sites, with their (sometimes complex) rewrites, and there would be a lot of tweaking to do to check if the new one interferes
Make a generic rewriting script that replaces all \x with %, interprets the result as UTF-8 and re-encodes as 8859-1.
:: pause to reread OP ::
I have seen that requesting the same file manually entering an URL like this works:
(i.e. apache receives a "GET /%f2.txt" request and serves the "ò.txt" file)
Are you here talking about literally typing in the 8859-1 form %F2? Not ò? That's fine. The only peril is if requests arriving at the server have more than one possible encoding. You would then have to do some preliminary stuff to identify the encoding of characters in the Latin-1 range. That's still not un-doable; it's just a few more lines.
Do all these sites live on the same server? If so, an alternative worth looking into is a RewriteMap.