We could possibly emulate both of these in MAME (aside from the PE6502's Propeller interface).
To emulate the Gigatron at the TTL level, we will need a lot more devices added to MAME's netlist library: 74138 (74HCT138), 74139 (74HCT139), 74157 (74HCT157), 74240 (74HCT240), 74244 (74HCT244), 74273 (74HCT273), 74283 (74HCT283), 74377 (74HCT377), 74595 (74HC595), 27C1024, 62256, CD4021... Even if they could all be supported, the simulation could surely not run at the megahertz-plus needed.
So we might need to emulate it at a higher level for now instead.
But it doesn't need to be dumped! It's open-source and ROMs are available. So it does not (yet) have a home at Undumped Wiki. Maybe in the Discrete page, but that's only for arcade games at the moment.
As for the PE6502...
The PE6502 ROM has not been dumped (though it largely uses Apple software). He does not offer it for free, so it would require the purchase of a PE6502.
Even after that - there's the unofficial "3 year rule", and it seems like we might be barely past that in the PE6502's case.