Smallest Mac Motherboard?

[dcr]

Out of curiosity, does anyone know what the smallest Macintosh motherboard is?  68k or PowerPC.

Given modern drive options like a SCSI2SD and/or FloppyEmu, I wonder how close a 68k or PPC Mac could come to the Mac Mini form factor.  (The original Mac Mini was 2" x 6.5" x 6.5"; newer Mac Minis are 1.4" x 7.7" x 7.7".)

Of the machines I'm able to measure, the Mac LC III motherboard is the smallest at 8.75" x 7".  Not quite Mac Mini size, but if you could get a smaller power supply, you might be able to do a Mac Mini-ish 9" x 9" case.

On the PPC side, I imagine the motherboard on the G4 cube would be the smallest, considering it was probably the inspiration for the Mac Mini and had a 7.7" x 7.7" footprint.  Don't know about height though.

 

[Torbar]

The Bandai Pippin motherboard appears to be about 7x7 if my very scientific guessing is correct(looking at a picture of it and using my thumbnail to guess how many 1/2 AA batteries can stretch across)

According to this post someone got System 7.5.5 running on it

https://www.applefritter.com/node/3510 

With that being said, im not sure how easy it would be to find just a motherboard for one

 

[ArmorAlley]

Would the 68K Powerbook motherboards be smaller than 7" x 7"? The PB 540C, for example, needs room for 2 bays.

 

[dcr]

 With that being said, im not sure how easy it would be to find just a motherboard for one

Probably not too easy and I would wonder about reliability since it's not really designed as a Macintosh computer.

Would the 68K Powerbook motherboards be smaller than 7" x 7"? The PB 540C, for example, needs room for 2 bays.

That was my initial thought too.  I don't have a 540c, but others I have or found online tend to be long.  The PowerBook 180c, for example, looks to be at just under 5" at the widest but is about 10" long.  Someone with mad skills might be able to cut the motherboard in half and stack the two halves on top of each other and reconnect the traces with wire or a custom adapter but that would be beyond my current skill set.  But, even with that, how much would that add to the height?  Then again, someone with such skills might be able to just rebuild the motherboard on a smaller custom board or something.