OK, so bear with me, I think I have figured out a 3-way sign and trade that lands Davis in Detroit, Moon in Boston, and leaves Miami without taking on salary.
This is making a couple assumptions. First, from what I have heard, Detroit now has $3.6 million in cap space remaining. That is of course crucial to this trade.
Also, I am assuming (probably mistakenly) that I understand how trades work with BYC players. Essentially, the team trading the BYC player away can only count 50% of that players new salary in their outgoing salary, while the team receiving the player needs to count 100% of that salary.
So if either of these are not correct, then this deal falls apart, but if they are, then this may be somewhat realistic.
Boston sends Glen Davis (signed for $3.6 million) to Detroit, and Gabe Pruitt ($825,497 non-guaranteed salary, with an option on August 1st) to Miami. They also send Cash to Detroit and Miami to grease the skids. This means Boston has about $2.63 million in salary leaving (because of Davis' BYC status), and can take back about $3.38 million in salary (125% of 2.63 plus $100,000). So Boston recieves Moon, signed to a deal starting at around $3.25 million.
Detroit sends out a heavily protected second round pick, and recieves Glen Davis and cash.
Miami sends out Moon, and receives Pruitt (who they can simply not pick up the option on), and Cash.