Well, I've actually done this in the past, back in my misspent youth, and I've pretty much concluded that mixing +48 phantom and a TRS patchbay is a bad idea- after wrecking some pricey equipment. There are 3 reasons:
1. Whenever you hotpatch (change patch setups when the rig is powered up), unplugging the patch cable shorts ring to tip to sleeve momentarily. With mics, this gives you an ungodly fullscale pop unless you remember to kill the phantom and mute the channel. I personally was never able to remember to do this 100% of the time. Bang! Bye, bye tweeters...
2. Worse than the pop is the potential for killing the phantom supply. Most preamps and mixers have phantom supplies that are designed to tolerate the occasional momentary short, but *not all* do. This leaves you the exposure of killing the supply in your ultra-cool high-zoot preamp just as you're setting up for The Big Take on The Big Tune with The Big Vocalist, and having to scramble for a fallback position. Not Good, even if the fix is just to drive to Rat Shack for a 500ma fuse.
3. Having +48 floating on TS of a a random patch point is just asking for trouble. Sure, it's an input, but if you ever accidentally mispatch it into another input or an output from a device that only has +-15v power supplies, you can easily kill the input protection diodes on the input/output opamp of the other device (or the phantom supply, or both). The *best* assumption to use is to set it up so that no matter what combination of points are connected, no smoke comes out. This *will* be tested at 2:30am of some marathon day when everyone is dead tired: count on it.
Hotpatching mics with the phantom power on is a noisy, nasty practice that can damage some mics and should be avoided like the plague, but the reality is that it is pretty much unavoidable (unless you work completely alone, drink a _lot_ of coffee, and have the working discipline of an ex-Marine drill sargeant). At least XLRs do not short, and actually connect pin 1 (ground) first, and disconnect it last.
XLR patch bays are for mic level signals with or without phantom, and TRS patch bays are for line-level without phantom- and never the twain shall meet, in my room. There are a bunch of companies that sell 1-slot rack panels with XLR panel knockouts (Full Compass, Parts Express, yadda yadda), and that makes it very quick and easy to build. I think you'll be happiest in the long haul with an XLR mic patch setup...
