Pffff... So many mechs, so little time...
Assaults: The pre-mentioned Behemoth, Masakari, and definitely the Hauptmann. I'd really like some Hauptmann/Highlander combos, and have always had a soft spot for the Scylla.
Heavies: Hellfire. It needed a resculpt anyway. ^.^ Jinggau as well-but just because I want one. Or two. Or a demi-lance.
Mediums: The Blacks-Lanner and Jack. Crimson Langur, Rabid Coyote, Men Shen, Clint. What can I say? It's my favorite weight class! ^.^
Lights: Fireball, Piranha, Nexus and Jackrabbit? We need more ninety-point mechs anyway.
I'll just leave it at that for now.
Although that Industrial Quad would be nice...