nut: I understood just fine, but thanks for your concern.
I disagree about it not being Firefox; we're mainly talking about changing some of the GTK widgets, where appropriate, to Wimp ones. This will have a dramatic appearance on the RISC OS appearance. The application of XUL should be very limited, perhaps to reorganise some menus. The result should still be very much recognisable as Firefox.
Yes, there is merit in making a brand new GUI for Gecko, but it is a considerable amount of work to write an entire new GUI from scratch and then interface it with what is probably a large number of APIs to Firefox, and such a path would not benefit other applications. Because of the work I've done on ChoX11 already, getting the existing UI running is at least reasonably straightfoward, and I'm working with code that's known to work elsewhere.
In time, there might be a browser on RISC OS that uses the Gecko engine and its own GUI. Perhaps the NetSurf UI can be adapted. But that time is not right now.
Sendu: no, your offer is not trivial, it is in fact very generous compared to what I've asked for. Many people have already contributed or promised to contribute in some manner, but there's still a lot more than haven't, and perhaps this might give them the motivated that's required to pledge a small mount.
As for you offer, I am happy to take you up on it, but before you get carried away, I think you would wany to see a non-style guide version to see what ought to be changed. And then, perhaps a 3rd party needs to be appointed to decide exactly when compliance has been reached, otherwise there might never be agreement. Someone from ROL or Castle if that's agreeable.
I will be publishing more information on the project in the next few days.