all in one place? probably going to be Photographer's Formulary. There is, to my knowledge, no dedicated dry-plate collodion, or wet-plate collodion, or dry-plate gelatin supply house in existence. Beyond the Formulary the closest you'd probably get would be Star Camera Company.
I'm glad to see someone else curious about dry-plate collodion. I've been curious for months and trying to get the time and money aside to get a setup together. Alas, being a student is conductive to neither acquiring time or money.
Also, in case you haven't seen it, there's a scan of a book knocking around the internet that lays out the process in minute detail for practical use. PM me if you want a copy and we'll figure out how to get it to you.
And, for my next trick: Hillotypes!