An adaptation of mtools 3.9.10 for VMS is available at:
http://antinode.org/dec/sw/mtools.html
It's not been tested very thoroughly, but some things seem to work
for me, and I don't think that the changes and the added code are
completely embarassing, so I'm admitting to them here.
As explained in the notes, this kit includes the original and
modified source files, plus VMS binaries for all three architectures
(Alpha, IA64, VAX). Where practical/convenient, the VMS-specific files
are segregated in a (new) "vms" directory.
If possible, I'd like to see these changes incorporated into the main
development stream. Questions and complaints are welcome.