Sorry to self-promote here, but if you're looking for some sort of generic library for writing a user interface, I've written one that wraps both the Win32 native and GTK+ APIs. Adding a Qt wrapper would be a weekend project for someone who knew the API (I do not.)
With the wrapper, you can write the UI once, and it automagically works on every platform, using its native toolkit. Kind of like wxWidgets, but without all the complexity and issues. And a Qt port would be trivial.
Do the same for hardware abstraction (unify the API for DirectDraw+Direct3D+GDI+OpenGL+Xv+SDL, etc etc), as I've also written a library for, and you pretty much have all the portability you could want.
The bad news is that it requires someone to patch these libraries directly into the emulators. I've had no luck convincing anyone to even try out my wrappers thus far :/
If you wanted an example, here are two screenshots of it:
Main window,
Configuration window.
Speaking of which, BearOso, if you want, you're free to use my Xv driver in Snes9X -- code is public domain and very small.
Your API really is impressive. It's more clean and concise than I could ever hope to do myself, and you've done a great job further improving the GTK part and different outputs support.
Then I really like your libraries Smile I do not know programming myself, but it sounds like this is just what we need for portability. I would really look forward seeing it in Snes9x. But it's up to the author of this GUI to decide of course.
This GUI is fairly cemented to GTK. Adapting to byuu's library would pretty much be another complete port. I'm not ruling it out entirely--I've done a couple ports of snes9x already and byuu's libraries are excellent--but the scope of such a change is greater than you might think it is.