Back in my youth, I built several HO scale modules with working trolley wire. My method was to drill 1/8" holes in the roadbed, drive music wire poles down through the Homasote and plywood, string tinned Radio Shack bus wire across the track and solder more bus wire to the crosswire to make the contact wire. Worked like a charm, even if it lacked the detail of scale...
Nowadays, I've been mulling over using Lionel 3424-77 telltale poles, brass rod and Märklin HO scale catenary to do something in O gauge. Will keep everyone posted if anything comes of it...
Mitch