Hi Hans,
This is most likely off topic, but it is an honest view.
If you really are just after an inexpensive Zynq devboard then the Parallella really isn't for you. It doesn't have many of the features you may need, and hacking it into something like what you want is against all that these guys are trying to acheive - for them the Zynq is the means to an end, a way to integrate their core to a low-end computer system.
However, Digilent are releasing something that sounds closer to what you need -
http://digilentinc.com/Products/Detail. ... &Prod=ZYBO. It might be $50 more, but it looks to be a far more general purpose board.
Mike