I have some Visio stuff for Partner, Legend and the old "refrigerator" System 75, as well as some common boards and telephones.
I've also gone to great pains to create Powerpoint icons that are to scale and color. Even if you don't use Powerpoint, you'll find that you can cut and paste these icons into Visio with acceptable results (God bless Windows OLE). My Powerpoints include some older stuff like Definity XE style cabinets and such.
I was frustrated in locating this kind of material as well. But you have the added benefit of me being such a picky person. I think you'll be pleased with my work.
I'll shoot you what I've got if you'll kindly send an email to tim [at-sign] dagwoodsystems [period] com (gotta fly below the radar of those pesky marketers, you know).
And for anything that I don't have, I would be more than happy to create it for you. I'm weird that way.
Look for a reply after the holiday. And have a great Thanksgiving everyone. You are all generous people for giving your time as you do!