Fairview makes the fittings used by many LP gas grills and campers. They supply the quick disconnect couplings with the shut valve built in.
1/4" coupling/valve QD-GMRVC4-4F, and the coupling w/o the valve is QD-GMC4-4F, and the male insert is QD-GMRVN4-4M, and dust cap QD-GMDP-4.
www.fairviewfittings.com