Jugglez showed me the other day that Mad Bull is developing a silencer type tracer unit with bright muzzle flash. (unlike the TM ver2 where they tried to suppress it)
It's just a prototype but it will look cool even if the muzzle flash could potentially give your position away. More realistic I guess.
Also posted here:
http://www.airsoftcanada.com/showthread.php?t=83345
YouTube - MADBULL Airsoft Revolutionary Tracer Silencer Tube Prototype-1
YouTube - MADBULL Airsoft Revolutionary Tracer Silencer Tube Prototype-2