Welcome to the forums and the unofficial site of the most obsessive Kubrick fans around! What has been the primary source of your collection? Do you have connections overseas or are you just picking up what you can on Ebay? Be sure to share some pics with us if you can.
As for the Kubie's Most Wanted List, mine would include several of the ones you listed. I've been lucky with a few chases, but the ones I'd most like to track down at this point are General Veers, Zam Wessel, and Yakface. For unproduced Kubies, my top five would probably consist of these guys:
2.) Hoth Rebel Soldier
3.) Kit Fisto
4.) Weequay Skiff Guard
Maybe Ree-Yees as an alternate as well as long as I'm making a wish list.