[Jason Abbadon]

The Build a Figure Modok from Marvel Legends is in scale with MU- looks great next to a few AIM agents.
Probably cost you about $40 on ebay.
Really worth it though!

I secon (or third?) a new HYDRA agent! I want the classic version with tunic and big tagert...er...Hydra emblem on the chest!
Ultimatum soldiers would be great too- and easy to prodce from already molded parts (well, a new head would be required).

A Reavers set would kick all kinds of butt- with Lady Deathstrike!