Thanks to Sami for sending along news of the ZXATASP IDE interface for the ZX.
The system is complete (for now?), with the versions of kit at v1.62 IDE and v1.50 MEM. Ok, this won't mean much unless you check the site. There's even some of these kits for sale, too!
And if you have an Interface 1 on your ZX, then don't worry, as a little hack-type fix will get it working with the ZXATASP's ResiDOS. Ok, so you can only use one at a time, but a simple command switches between them. It even works well with the latest SE Basic (tho' we'll see what happens when v0.8 is released after beta testing is finished).
Now we just need to wait for someone to automate all of this into a handy multi-system commander. Yes, one program that handles MB02, TRDOS, ZXATASP, +D, ... hell, even tape. Anyone have the time to spare?