I would say an efficient way to produce one, assuming your budget was about $800 per year, would be something like this:

2009 - Buy Axanthic Female
2010 - Buy Pastel het Axanthic male
2011 - Buy Bumblebee male (breed pastel het axanthic male to axanthic female, hold back 2012 female pastel het axanthics and pastel axanthics)
2012 - Breed Bumblebee male to axanthic female (Hold all 2013 bee het axanthics, pray for a boy)
2013 - Breed whatever you want to your axanthic female (enchi? pin?)
2014 - Breed 2013 bumblebee het axanthic male to 2012 pastel axanthic and pastel het axanthic females. Sacrifice jumbo rats to BP gods.
2015 - Hatch Killerbee Axanthic, throw big party, invite BP.net crew.