As for separate devices that use the gyro principle these devices actually stabilize the camera and keep it steady. They have to be heavy because if they are not heavy they are not effective and they are also expensive. They were available long before the in lens or in camera were available. They don't need a computer to run them just power the spin the gyro.
Why don't you just buy a stabilised lens? Canon, Nikon and Sigma sell a whole bunch of them that will work on 35mm film bodies; it's Sony that does stabilisation in the body instead (therefore no stabilisation available on Minolta SLRs).
You want an external stabiliser? It's called a tripod.
Thanks for the DIY link...
Did you follow to where Glenn Turner is releasing details about his low-cost Gyro in a week or two? Very timely.
One thing that could help is the "string pod."
Mount a tripod plate onto the bottom to hold a section of string (preferably strong twine) about 4-6 feet long. With the string unrolled to the ground, step on it to keep it in place and pull up on the camera. The tension will give you anywhere from 1/3 to 2 stops increase in stability.
The amount that you can increase your shutter time depends on several factors, but I've gotten decent results with it in a pinch.
I believe that stabilization you refer to David would have been available in film cameras and lenses if digital had never been invented, it's interesting to speculate what modern film cameras would be be like if the R&D budget and effort spent by the manufacturers on digital imaging had been spent on film photographic equipment.