For all of us that have been grumbling over the lack of aftermarket decals for WW1 Tanks, Decalcomaniacs have issued a new set "WW1 Romboids #1", with 1/72 scale markings for Mk I-III. (Yours truly have helped them with info, but I want to point out that I am not involved in this company and gain no profit from it. Just glad to assist.) And I understand that George Eyerman have plans to do more WW1 decals.
Check it out at http://cgi.ebay.com/1-72-Decals-Decalcomaniacs-WW1-Rhomboids-1_W0QQitemZ5989504445QQcategoryZ2588QQcmdZViewItem