I was up to visit Rob Gibson's studio in Gettysburg over the weekend, and was looking at how neat the ambrotypes are. I've got some 5x7 dry plate holders I'd be interested in learning with, and I just don't want to go through the hassle of getting another entirely new camera, with all the attendant wet plate gear.
For whatever it's worth, the ambrotype effect (scattering from the silver image showing as positive against an absorptive black background) is perfectly operant with gelatin emulsions; I know of no reason you couldn't make ambrotypes with dry gelatin plates (some purists may claim the gelatin emulsion won't look just like the collodon, and they might be right, but developing with collodion chemistry would be a good start).
From what I hear, though, don't trust the Rockland Colloid "tintype" developer; it's bad about as often as it's good, and their (gelatin) tintype emulsion (which would also work for ambrotype) is too expensive to waste that frequently...
Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.