I've been looking around for some decent low cost ATC spindles with either ISO or BT tooling. It's a bit of a tricky area for DIYers as of yet, but I'm hopeful in time they will begin to emerge.

So far, one that looks like a good bet is this one:

Built-In Motor Spindle - MicroLab Precision Technology

Does anyone have any experiance of this company?

I have attached a diagram of their M3-LMSN spindle. This is water cooled, pneumatic BT30 ATC, 8Kw 24kRPM, 100mm diameter body, with mounting flange near the base.

I recieved a quote of $3000USD