Great ideas, thanks.
I have asked the creator of OpenArch a few months ago to add the link to the archive in the citation. I sometimes see it, but below the text, but in most cases it is still hidden in the button to the original document.
It shouldn't be to hard to make it though, let me think about it. OpenArch offers an API which is a real great help.
AlleFriezen and the other archives using the Picturae software: that is a bit harder as I do not have the capability yet to access that data without importing the whole set (and I do not want to create yet another search machine at this moment). I use wiewaswie to search the records myself, as Jan states.
At this moment I have little time to do programming, due to my work situation, and want to focus on the link between profiles and documents and a way to personalize your citation (without breaking general citation rules aka APA rules). I am afraid that is already quite some work. When someone with Pyhon 3 experience wants to help: send me a PM!