I'd like to extend the UDT module with the ability of showing a detail page after a click on a URL field. Preferrably this would work by simply passing the moduleID and rowID as form/querystring variable. On the detail page any module could then pick up the values and display details accordingly.

Now this is probably a question that's been asked before and I believe it's on the UDF roadmap too, So before I start hacking away, does anyone have any pointers beforehand?

We support a single query string parameter inside the upcoming release. 

One of ots uses cases is master/detail view. I will add a simple example XSL style sheet do show how this can be used.