Dragonlasers sells them, or you could jump in the CNI group buy, can't think of anything else off the top of my head. Yellow lasers are not cheap though.
Think Lasers had two kinds one pen and a high output 18650. Both were ridiculously expensive. You can check Vectra lasers and Jet Lasers, they seem to have a good part of the spectrum in production.
Hackzaw is working with Jet on a GB and prices were darnn good.. reminds me to place my GB order...Ciao for now