Gabe and Schaef hashed this out awhile ago: http://www.cactusgamedesign.com/message_boards/index.php?topic=12040.0
Wow, I forgot how long that went on. What a good read. 
Lol.. it took me awhile to read also. My original thought was that you could not play Abe's Servant, but I always like to go back and research for confirmation. Summary for those who don't want to read the entire thing:
Q: Can I play a negate of the original color my hero was before he was converted with Gold Shield?
A: Yes, no, yes, no, yes, no, yes, no, yes, no, yes, no, yes, no, yes, no, yes, no, yes, no, yes, yes, ok.
