i realise something while i was lurking, there is no sub-forum for used, custom built, or unwanted RPi in the "Ye Olde Pi Shoppe" forum.
they got "cases", "add-ons", "other stuff", and "wanted" sub forum, why not used RPi
there seems to be a demand for it just from looking tru the wanted section.
i believe there are people who wants used or custom built/stipped board
and the "wanted" sub forum is flawed, since if saomeone want something, the post their request, and wait for some one to reply, that is if only a potential seller saw it.
but by having a Used/Custom RasPi sub-forum, people can just browse for it.
for example people who wants to buy a Rpi based gaming system
i, personally, planning to build RPi cluster PC for learning in the near future .
but i am a enviromentally conservative person, and i preffer reusing old product than buying a new one if i can.
so if i can, i wanna buy old working RPis that no one uses or want,for any reason, and use as much as available for each nodes, and buy new for the rest.