Hi! Thank you very much!
I already attempted some development for the Z88 in the past, with CHIP-OTTO, my portable CHIP-8 virtual machine. The Z88 version was almost complete, but then I focused on the ZX Spectrum Next port and did not finish it . You can still see a gif in the CHIP-OTTO project page.
I would be definitely interested in the Z88DK port, maybe starting with a simple build of the standard version and then making a specific version optimized for the Z88 display. At the moment I am very busy with other projects, but as soon as I'll get some free time I'll try to prepare a Z88 build!