As mentioned above, the list of font vendors is annotated with information about non-Roman alphabets. Commercially, Masumi suggests that Linguists' Software is the current [ed: as of 7/92] leading supplier of non-Roman fonts.
Ian Tresman contributes:
The Multilingual PC Directory is a source guide to multilingual and foreign language software, including fonts, for PCs. Over a hundred different languages are included, from Arabic to Hieroglyphics to Zulu. A 1200 word description is available from the publishers, Knowledge Computing, email: 72240.3447@compuserve.com.