http://www.scopemounts.com/insta.htmI found this site. Kinda fun because it was close to my hometown growing up. They had one for the Enfield 4 & 5's. They are non-drill/tap style. Even have a picture of one in service. Not super clear, but gives you an idea.
Called and spoke to the owner about my 8mm mauser. He said he would put the mount on for me over Easter when I visit my parents.
If your interested:
S & K Scope Mounts
RD 2, Box 21 C
Sugar Grove, PA 16350-9308
Telephone: (814) 489-3091
Toll Free: (800) 578-9862
Fax: (814) 489-7730
Might be pricer than some, but they are willing to talk to you and help alot.
Cracker