Ever since Jeffrey Lee began work on porting RISC OS to developer boards such as the BeagleBoard and IGEPv2 there's been interest in putting a case around them to make them into proper computers. Both ports are still firmly in progress, so a finished-off A9-style computer isn't likely to appear for some time. That hasn't stopped some hobbyists having a go at making their own. This one looks particularly impressive:
 

 
There are more pics and description here on the ROOL forums. The nutBOX comes hot on the heels of Dave Thomas's lego housing for his IGEPv2 here, first reported on riscos.info.
 
There's still some way to go before the RISC OS OMAP port is stable enough to drive a general purpose computer suitable for everyday use, but in the meantime, plenty of people are having fun with what already exists...