MimeMerge is a Perl script which merges two MimeMap files, ensuring the resulting output contains every mime-type, extension etc. from the originals. It's not been extensively tested but seems to work ok. Given that there should only (I think) be one RISC OS file-type per mime-type, a conflict in the two files here is arbitrarily resolved. I made it because I have two MimeMap files (one in !InetSuite, one in !Boot) and I'm scared to delete either but wanted to make sure they were both up-to-date. 

MimeMerge requires Perl