[SIGCIS-Members] question about DIY computing in the 1940s/1950s

[Evan Koblentz]

While writing about the National Bureau of Standards' SEAC tonight, I 
began to wonder: what are some other examples of computers in the late 
1940s and early 1950s that were developed by customers because it was 
easier than buying one commercially?  I'm specifically interested in 
machines that were completed and put into real-world use, not those 
which were experiments.