Did colt ever make a 605 from a 1:14 barrel?  Has anyone around here tried it?

I don't think so...I think they dropped the 1-14" twist at the 601 and never looked back.

Ben, for what its worth, I've barreled quite a few AR uppers with 1-14 twist. They are varmint hunting rifles, shooting 45-55 grain varmi t bullets and are prarie dog deadly accurate.
    You have to remember that the military went to the 12 inch twist for the use of long tracer bullets in 55 grain. I wont even say how long some of my shots have been on prarie dogs with 14 inch twist AR's, but lets just say is there is no reason to not use 14's if you stick to light/short bullets.

1-14 twist is fine for 55-58 grain and lighter unless your operationally operating where the atmosphere is as dense as it can be I.E. above the arctic circle in in -45 F temperatures.