Old for New are around but very hard to find... looking around I found this URL in Canada,
electronics are under Exotic Slide Rules, as far I can tell.
Page below, look for: Hemmi/Sun 266 Electronic Engineering 10" Duplex Rules
http://www.sphere.bc.ca/test/exotic.htmlthis page has some electronic rules, however their highly priced and sold-out; however if you keep a keen eye
on this site, you could get lucky.
Here is the main page for all there slide rules:
http://www.sphere.bc.ca/test/sliderule.html