[Psientist]

It is possible to create custom, or modify existing, magic items and assign them to indies. Just look at my Antilarium metamap.

Creating a .dm file depends somewhat on your operating system, but it's just an ordinary text file with a funny extension. I suspect a "rename" of a plain text / notebook file in windows explorer will do it, it certainly will in Mac OS.

in unix it's "mv filename.txt filename.dm"