Yes eBay is out. I've been looking for a while. I have 2 now 1 for left 1 for right. One of them died so I will have to change both amps or find another nakamichi. The nakamichi did 240@2ohms so it was well suited for my needs. I can switch it out for a diamond d3 400.4 or jl e2150 but neither fit the bill.
I might have a pa-302 coming soon, which does 160 x 1 @ 4ohms. Or did you need that 240 @ 2ohms?
If you need the pa-301, there are a few quite often on Yahoo Japan (they don't have an ebay), but you will probably be spending around $150 total after shipping...