Yeah not sure about what you guys in the UK get paid, but the going rate for an intermediate Java developer here in the states is 80K/year. Junior devs start at 60K. I make more than double what a junior dev gets, because I work in Java, C/C++ as well as advanced client side web stuff including AJAX, CSS and general DHTML.
Some of my friends working in the game development field (C++/Windows/Mac) make more than I do for their specializations. I consider OS development to warrant more money from a big company.
Given that Hyperion and AInc are much smaller and the given the passion that most Amigans feel towards their platform I *could* see working for beans if I had a supplementary income. The benefit to one's resume and self satisfaction would probably pay for the development of the OS.
I think, and hope, that Hyperion gets the rights to sell the OS. It, for us, would be the best chance most of us would ever have to start enjoying the OS.