I had the same results steve with google, you maybe better off going for an AC motor and inverter over DC as they are low voltage and high current.

They are a bit bulky but cheap and you can control the speed easy, use a small AC three phase motor and an inverter for £250 and you now have a 1KW varible speed spindle.

If you use a DC motor you will need aditional electronics to control the speed and high current dc drives are not that cheap. All depends what you want really.