… I think.
There are several books that deal with building your own test equipment like power supplies, meters, frequency counters, timers, function generators, and battery monitors.
It would be nice if SparkFun could make available all of the components so that customers could just buy the kit and assemble it themselves. Or, you could merely make a parts list available and skip the extra inventory item.
Also, since you guys have some engineers working there, y’all could update and improve the designs and publish a book via [Lulu.
The books are:
Pepper, Clement C., Build Your Own Home Lab
Petruzzellis, Thomas, Build Your Own Electronics Workshop
Bergquist, Carl, Build Your Own Test Equipment](http://www.lulu.com)