High speed spindle question

I'll try to format the following so it can be read.

A bridgeport is a great mill, but lacks the high speed required for
miniature CNC work and engraving. I'm thinking of attaching a high
speed spindle to my Bridgeport spindle with an Erickson 30 holder.
It would hang on a bracket similar to what Jon Elson shows on his web
site, but under the spindle.

http://www.pico-systems.com/wwspndl.html

Any preference for which electric tool is better for this application
(die grinders, trim routers and cut-out tools)?

So you don't have to look them up (using Dewalt as an example):

Tool type Speed HP/watts Current Collet weight

Trim Router: 30K rpm 7/8HP 5.6 AMP 1/4" 4.75 pounds
Rotary Saw: 30K rpm ? 5.0 AMP 1/8 & 1/4 3.2 pounds
1-1/2" Die: 25K rpm 350W 3.0 AMP 1/8 & 1/4 3.25 pounds
Grinder
2" Die Grinder: 19K rpm 485W 5.0 AMP 1/8 & 1/4 6.0 pounds

Even though I may have to create an 1/8" collet, I'm thinking the
trim router gives the most bang for the buck, but I'm interested in
your take on it. Also interested if you think collets may be
interchangable between the above.

Thanks again and regards,
Jeff