Well, here's what happened. I kept looking at the Hermeyer ESL construction details and trying to figure out when I might come across 400 or so hours of free time to finish the job. Then I get one of those ads from David Lucas for the Double Impact system. Along with it comes a license agreement about the instructions containing trade secrets. This makes it difficult to discuss the kit in detail so I'll just say I don't recommend them to my friends.
In the interim a good article on ESL construction came out in Speaker Builder. I used some ideas from that and an ESL web page to build panels out of the 15"x6" perfed, anodized aluminum panels I made as per the Hermeyer articles. Using polcarbonate on one and styrene on another I built working panels. After all this I now feel I have a good combination in mind for building budget ESLs. I feel I must acknowledge the helpful input by Barry Waldron, but also say that he recommends wire stators rather than perfed metal. When I have more time and money I'll probably build something along those lines, and would advise the "no compromise" builder to get "The Electrostatic Loudspeaker Design Cookbook" (BKAA-20) from Old Colony Sound.
For panels I'll get two sheets of Lincane and have them split into four 18"x24" stators (total $35 at Berg Hardware in Pasadena). For spacers I'll take 0.040" styrene ($14 for a minimum buy). For adhesive, the double-stick 1/2" 3M acrylic in the SB article (PC9485 I think). To make contacts I use window alarm tape. Mylar and graphite for the diaphragms and you are there.
Thanks go out to Dave Smith in Texas for cluing me into American Science Surplus in Skokie IL. Get their catalog. Another fine source for obscure stuff is McMaster Carr in CA. They have a catalog on CDROM they'll mail to you. Fairly soon I'm going to need to unload some parts. I have about 80 of the 15x6" anodized stators plus a bunch of spacer material and conductive tape.