Advice needed for Makerbot rebuild

To be honest: I posted this to the makerbot forums. I have had limited luck on those forums before so I am also posting here. I’d like to be able to get input from reprappers as well as makerbotters.

I’m rebuilding a late-model cupcake for fablab Boston. It has had some parts stolen, and I’m looking for advice on what route to go.

The two issues are that the motherboard has been stolen and it has a mk4 extruder. I know that the simplest thing to do would be to buy a new motherboard but the direct replacement (1.2) seems to be perennially out of stock.

Then we get to the fact that it still has a mk4 extruder. Since this will be used to teach kids how to print and do 3d design, I would really prefer if it had a bulletproof hot end. I think that generally means stepper-based, either mk6, mk7, or a wades style printed one.

Option 1_ I can get a motherboard v2.4, stepstruder mk7 complete kit, and an arduino mega 2560 from Makerbot for $85+$229+$65=$379

Option 2_ I can get a motherboard v2.4, another stepper driver, a stepper motor, arduino mega 2560 from Makerbot and some printed wades extruder parts for $85+$92+$65+free=$242

Option 3_ I can just get the motherboard v2.4 and an arduino from Makerbot and fight with the old dc extruder for $85+$65=$150

Option 4_ I can get a full reprap-style ramps board from with stepper drivers, an arduino mega, a stepper motor and printed parts for a wade extruder for $130+$16+free=$146

Am I missing any better options? I’m leaning towards option 4 currently, but I could be persuaded. Am I correct in assuming that I can’t use repg on a RAMPS setup? That would basically be a full reprap toolchain conversion.

I’m honestly fairly excited about moving to a slic3r / pronterface toolchain because repG has always been fairly buggy and I feel like the cupcake is not that well supported in recent versions.