I'm sorry but i fail to see a question in this thread.
If you're looking for a PATA RAID DAS, good luck! You probably won't find it.
Its a terrible solution anyway, since the DAS cannot be used with any modern drive and only tiny old PATA drives you have at the moment. So you spend like 3 times as much as a 1.5TB drive, and still get lower reliability/speed/capacity and takes 6 times as much power also.
So are you sure you want to go in that direction? In my opinion, its a clear waste of your money and effort.