Very interesting.
Thanks!
I think there may well be a mini FT-5 in my future as a backup printer.
215x215 seems like a good size and would meet the vast majority of my needs.
I used the original FT 12 volt PSU for another project (non-3D-printer-related).
However I have another nice 24 volt supply on hand and so I would just go with it.
I have spare motors, extruder parts, hot end parts, a display, cables, idlers, fans, and much more.
All I would really need to buy are the bed, some framing pieces, belts, pulleys and a controller board.
I am thinking in terms of scaling down the dimensions of the FT-5 proportionally to fit the smaller bed and building a generous electronics enclosure in back as you did.
I'll bet it would be very rigid and could handle very fine layer heights.
I have metal-working tools so metal work is not an issue (I did notice all your nice metal parts).
Hmmmmm..... this could be a lot of fun. 
(so far no pestograms.......)