There was this guy selling a "male mannequin head" on eBay for years that was quite obviously a Patrick Steward head (and it looked very good) but he had no idea what he was selling and had several of them. I haven't looked in a while but it's worth taking a look though it may take you a while to weed through all of them. From what I remember they were very affordable.
eBay user ID was donnyaol.com He had the Picard and an Arnold. I bought the Arnold a long time ago and was pretty pleased with it. Very good cast and very sturdy as well. Users last feedback was August 2010 and has no items for sale currently.
With that big of a lag in feedback he may not be selling them anymore.