Some time ago I dumped the bank-switching ROM for the Tiki-100. Allthough it's pretty well documented, it reveals a few banking posibilities not described elsewhere.
Check out the Technical/ROMS folder here:https://www.dropbox.com/sh/3fyj6gk7xr84mgx/AAAy5YwYMGDKs7gGJSPlhDAta?dl=0
Basically, by enabling both Video-RAM and the ROM, you will end up with ROM at 0000h-3FFFh, video RAM at 4000h-BFFFh and regular RAM at C000h-FFFFh. Video RAM will start in the middle of the screen bitmap and wrap around to the top at 8000h.
Expansion cards also have the ability to disable any memory on the motherboard by pulling one signal: all of RAM, ROM and Video RAM is removed from the memory map. The 8088 expansion card might be doing this when it's set to master the Z80 bus and it's not accessing C0000-DFFFF.
The other documents there are findings I've mainly documented for my own use. It's a very compehensive description of the IO map (including harddisk), the expansion busses (including some details on graphics waitstate timing), the software disk functions of the latest monitor/kernel, and what I've been able to discover this far about the 8088 expansion board interface.