A few people have asked about this around the forums and I now have some extras so...
I am selling some DSP-1 kits!
I've recently come across a few donor carts and have been busy making labels and desoldering.
I made these for myself and a couple of friends and now I have some left over that I'll be selling over the next few weeks.
Also, here's an installation guide:
Here's a picture of some carts that I've cut a hole out (for SD cards):
I originally was offering these for less to forum members, but since I only have a few and am having no shortage of interest via eBay, I'll just sell them there.