Hi Thorsten.
Great stuff! I have been hunting all over for exactly this solution. I should have known to come check here first ^_^
I'm keen to try this out. A question or two if I may?
Do you have any ideas why USB hubs are not working? You mentioned power issues before - have you (or anyone else) tried a powered hub? Or do you have any other thoughts about how that might be fixed?
If not, then I might try another board with more than one USB port, like say the new Raspberry Pi Model B+. Granted, that will involve porting MIOS :/ but I think FreeRTOS runs on it already at least.