I'm planning a new home shop and evaluating options for a DIY mill build and came across these cast iron machine frames. Has anyone used them or have thoughts on doing a build with them?

https://www.ebay.com/itm/DIY-VMC-Sty...-/193308825936

I would want to build out the head with a high speed spindle (10-20K). Primiarly used for aluminum prototyping and parts (~150mm x 300mm x 80mm). Surface finish and accuracy are important points to optimize around. For fun I'd run the system off a Beckhoff IPC controntroller with Beckhoff or Mitsubishi servos. Idealy I think a DIY Datron like machine would work out well for the work I do, but having the option to do heavier cutting would be more versitle for my use.

Haven't found any builds with these bare cast iron frames, out of all the options I'm considering it seems like a solid path to go down.

Options considered:

+ Extrusion Frame - Vibration are stiffness are to much of a concern to go down this route.
+ Aluminum Bolted Plates - Would turn on looking nice, but vibrations are a concern
+ Steel Bolted Plates - Vibrations are a concern
+ Expoxy Granite - Don't have a machine large enough to mill the entire frame after casting - could outsource but seems like a ready to go cast iron frame might be easier
+ Welded Steel - I like the flexibility of getting plates laser cutting and designing a frame, but don't have a great welding setup at the moment
+ Sieg/Grizzly Conversion - Well documented path, but I'd likely end up replacing everything expect the frame

The comps for the machine I'd like to build it a DIY version of a Tormach (slightly smaller is fine) or a Datron. If I went the Datron path I'd likely get a small manual mill for general work as well.

My CNC background: I've converted an X2, had a Tormach and VF2SSYT. I design automation equipment for my day job. Looking for something small to keep around for weekend projects (and for this built to be a weekend project itself).