[plt-scheme] Using a UI language for PLT Scheme

[Please pare follow-ups.]

We had some students at Brown play with intergrating XUL into a
programming environment being developed here.  It seems way too
premature for significant use.

The others don't sound like great options.  It seems impossible to
mention Qt without provoking a Freedom war; XAML is, afaik,
platform-specific; and I believe GNOME/GTK doesn't run as widely as
wx.  Only Mozilla/XUL seems to have the same breadth.

I don't think this is a bad idea in the long run, but I just don't
sense these technologies are up to the mark yet.

Also, when you say "there are programs that translate ... to ...", how
complete and thorough are they?  Do they really accept the full
language as input and produce legal output?  Or are they typical
prototypes that don't work too well once you leave the subset of terms
the author found easy to translate?  (Wouldn't be the first time.)

Shriram