Another contact point: Metro Business Systems have a quantity of SONICblue branded units (these have the same black casing as the Dell, but are no longer branded as such). They're identical in performance and capability to the Rio units, but just look different.
I've been given a contact for getting hold of these units - Frank Pelli:
fpelli@metropc.com
If you want a unit (not sure on the price, I'm guessing around $150, and I'm not sure if they'll ship to Europe, but it's worth a try) then email him with a return phone number and he'll get someone to call back & take the order.
Hugo