I'll second Andrew's suggestion to go straight to the national/international organization; many clan socities have clan historians/sennachies, etc. who specialize in this very thing, as well as clan museums, heritage centers, etc.

Here's one page to look that is the best source for the translation, INMHO:

http://www.clanmacleod.org/about-mac...nd-tartans.php

This web page is for the worldwide Associated Clan MacLeod Societies.

Cheers,

Todd