One system I fiddled with was the 8088 Zenith SuperSport - zdsupers.
According to the documents it uses 3.5" 720K floppies. The fdc_xt card allows either 5.25" or 3.5" drives - is it possible to specify the drive type from the driver source in the MAME ISA system? Changing it in the running machine does not "stick", so you have to change it every time you start MAME.
You can use MCFG_SLOT_OPTION_MACHINE_CONFIG after the slot is defined, see tandy1t.cpp for an example. To make the device unchangeable as in a laptop use MCFG_SLOT_FIXED(true). For the ISA slots, the last parameter in the MCFG_ISA8_SLOT_ADD does the same thing.
Does anybody have an original boot disk for the 8088 SuperSport? I have found a Zenith branded DOS 4.0 version that boots on PCEm but halts with "Divide overflow" in MAME.
Really? Where'd you get it from?