Thanks for the reply... I think you may have had a different problem than the one I'm trying to solve. I've already built a CPT archive specific to each of my post types, but submitting an empty query seems to just take me to a page built from index.php. I guess my problem is that I'm struggling to find a way to include my CPT in the query string automatically.
Basically, I've got a few custom taxonomies (resource_type, topics, timeline) which I want to query within a CPT called 'resource'.
I can access the cpt archive by going to http://site.com/?post_type=resource
But when I make my query I lose this parameter... I get a query string that looks like, for example, "http://site.com/?resource_type=magazine-article&topics=&timeline="
What I want is to have the resource archive automatically add "?post_type=resource" to query strings, resulting in query strings like this: "http://site.com/?post_type=resource&resource_type=magazine-article&topics=&timeline="
One way to solve this would be to add a dropdown for post types, but for some reason I can't seem to get this to appear.
Sorry if this is the wrong place for all this... I think I may have to start my own support thread.