Magnifier

You might want to try the MicroMark tool people. They cater to the modeller, and usually have a variety of magnifiers available.
Ther website is: www.micromark.com You should also be able to get on their mailing list.
Gip Winecoff

Have you tried looking in art shops? i am sure i have seen some in them if not what about looking on websites for the visualy impaired for suppliers of that kind of thing. there are bound to be companies that deal with them that advertise on the net...hope this helps.....Greg