I agree with you on the virtues of Glock and they make sense for the Coasties since the tennifer finish would be nearly impervious to the salt water. Plus, they're dishwasher safe! But I think that the FBI has also gone to the Sig IIRC. Except HRT which uses 1911 45's.
I have a Glock M27 and some of the M22 Hi-Caps to use for backup on trips. But I prefer to use my Sig P245 for my usual carry gun. Something more ummmmmm authoritative about a .45! I've owned both a Glock 21 and a Glock 30, but I find them a bit too blocky in the ergonomics area. Like holding onto a 2x4. But then, I have rather small hands. So I like the Sig P245 (w/tritium night sights) and I use Sig P220 8rd mags as backup. I'll eventually get a Sig P220 with an integrated rail so I can also mount a SureFire X200 gunlight and perhaps some Crimson Trace laser grips. This will become my dedicated house gun. On long trips, I'll take it as a compliment to the P245 and for my wife to use in a crunch.
http://www.guncrafterindustries.com/50_gi.htm
My new toy......ordered , yet to arrive. Pricy but one of the gotta have toys.
Report forthcoming....the 45ACP was just so small after I saw this beast......;o)
Stay safe !