I don't know if this is what you're looking for, it's a RPM Activated Switch made by MSD Igintion.

http://www.msdignition.com/1rpmacc.htm#anchor63270

The RPM is selected by using a RPM Pill. They also make RPM Window switches that active in a certain 'Window' aka RPM range.

We use them all the time on fast 'street' cars and race cars.

-Chuck