Although not ideal in your scenario where "deployment" of the par isn't necessarily the same as the system building the par (ie. having all the depend resources in once nicely organised "release" folder). You could always just have your dm-server point to your internal *OSGI SAFE* maven repository(s)...
We currently have an internal osgi safe repo an our local build bundle repo which a local instance of the dm server references.
This works quite well for development (sans the fighting of the dm-server bundles vs the repo bundles (which is where I break down and cry))
But I too would like a nicer description of the ideal "release scenario" with respect to deploying on an "out of the box" dm server.
I also forgot to mention that the maven dependency plugin also has a transitive dependency inclustion feature which might help you...(merging all the dependencies used in a project hierarchy is something i'll leave to you)