Why is it that people assume that just because most do it a certain way that this is the only way it can be done? The home made ARM board that I am currently using has a 2 x 217BGA SoC, an external DDR2-SDRAM, NAND FLASH, A VGA RDAC, an ethernet module, 2 x USB, and exports the RGB and sync lines and 50 GPIOs. And this is just something that I threw together in a couple days to get me by until the Pi comes out. This was done with a 2 sided board, on one side all the extra space between traces is used for a ground plane the other side the same for a power plane. It has problems, it is far from the best, and it is slow (SoC 400MHz, bus 133MHz).
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers