Building a custom power supply for an old TT

Every now and then, I come across a Technics SP-10Mk2 or Mk3 which is missing its power supply. Once, I have even found a PS-less Exclusive P3.

I have never taken the plunge because I have no idea that it can be remedied (though the SP-10Mk2 PS is occasionally available separately).

Has anyone ever ordered/built a custom power supply for a high-torque DD table?
Does doing so require schematics? Service manual?

If not, what does it require? And can anyone recommend who can build one for me and at roughly what cost?

Direct email responses (including from MFRs looking to avoid getting hassled by the Bored if they respond) are welcome.
I was searching another topic and saw this post. For the Technics tables, there is absolutely no problem to build an outboard PS to take the place of the original. All you need is a PS that can make 140VDC, unregulated, plus regulated supplies of 32.5V and 5V output. The current requirements are minimal. It would not be difficult to surpass the PS that comes with the MkII in terms of quality of regulation and filtering, and the factory schematic is available for a small fee off the internet (in the context of the MkII service manual). If you are "all thumbs", there is a company in England that makes a brand new supply for the Technics MkII, for about $700 at current exchange rates. It looks to be possibly superior to the original in some ways, plus of course it is all new parts inside. I would not hesitate to buy a MkII or a MkIII without a PS, if one were available.