Yes - I realise that you need more than just a UCS font manager for apps to work correctly with Unicode! If only it were that simple! Thanks for the source code pointers; I'm trying to get to grips with just how well RO5 handles UTF8 without actually having a machine that can run RO5 - not easy!
I suppose what I really wanted to ask was, if you could softload the UCS font manager on RO4 or 6, had a suitable font (converted from TTF with the EFF's tool, for example), and ran an app that was Unicode-aware like Netsurf, would font display work properly? Does Netsurf check the font manager version number, or the OS version number to decide how to interface with the font manager, I wonder?
The system font issue is interesting. Any hanzi or kanji really need twice the width of roman letters to be drawn sensibly, so I think single and double-width characters are a must, as you say, not just for Japanese, but for Chinese and Korean, too (and probably other languages).
I'd be very interested to see the Unicode-aware version of !Chars. Hopefully it'll surface sometime soon! Actually, there's a tantalising screenshot on the rufl website ([link]) that looks a bit like a Unicode-aware !Chars...