Wow, when I read this I thought that this is something that I might have written. Anyway, you might be able to get by with many of those features in 2 phones. On the other hand you might have to end up with 3.
1) I think most Androids have GPS. What you need is maps stored on the device for navigation. I have a Garminfone, which is GSM, and the GPS works great off network. Any Android with CoPilot would work, BUT CoPilots is primarily for vehicle navigation. What specific GPS features do you want or need?
2) You didn't say how portable it needs to be. A Motorola M800 probably has as good of reception as any, but it is a bag phone. A phone that works on 800 mHz is better than higher frequencies. That means Verizon or AT&T. From friends in my area that have Verizon, it seems as if the Verizon network may have better rural coverage.
3) I don't think any phones have great battery life once you start using GPS. Consider carrying a spare battery or two.
4) I haven't seen an external microphone jacks on any phones that I have seen.
5) What do you consider to be great quality camera images. I know the megapixel rating isn't the only thing to look at, but there are certainly some phones with 8 megapixel cameras.
6) If you are seriously looking at gloved hand operation, you really ought to consider getting the gloves that work with touch screen phones. I don't have a pair, but I have seen them on line. They transfer heat from your fingers so that you can keep your gloves on and still work you phone.
7) The off network feature will be an iDen exclusive. I have several like this and they work quite well for short distances. I have hoped for a long time that this would come to CDMA and GSM phones, but I doubt I will see it anytime soon.
Surprisingly, I don't see that you mentioned anything about rugged and/or water resistant, so that must not be a huge concern or yours. Anyway, I Googled and found the Top Rated Verizon Camera Phones 2011 / June 2011 http://www.phonerated.com/top-rated-best-verizon-camera-phones-by_network I would probably just get one of those first three: HTC Thunderbolt, HTC Droid Incredible 2, or Motorola Droid X. Then I would get CoPilot for GPS. Next up would be an OtterBox to protect it. Then a pair of those gloves that work with phones. Also, pick up a spare battery or two. Finally, get a couple of used Nextel i325s for Direct Talk. The i325s have a fixed antenna, thus they probably have the best range on simplex. You could even consider getting a Wilson Sleek for improved performance in the vehicle. Also, Motorola probably has OEM windshield mounts for vehicle navigation with the Motorola Droid X.
I just bought my son a Motorola Defy last week and it is a nice phone. The Casio G'zOne Commando is also a contender. However, both of them only have a 5 megapixel camera. Sonim makes some rugged phones, but I think they are all GSM, thus no chance of using Verizon as your carrier.
Of course, to further confuse the issue, there are some other multi purpose devices that might be worth looking at. For example, the Garmin Oregon 550t is a handheld GPS that has a camera. Also, their are rugged, waterproof cameras, some of which have GPS!
If money is no object, the TerreStar GENUS Windows Mobile 6.5 Professional smartphone from AT&T, which provides both cellular and satellite connectivity, might be worth looking at. You could look around for Garmin Mobile XT, which comes on a 2 GB microSD for GPS navigation. If you didn't want or need satellite service all of the time, you could use just the GSM part on A Fee & Fee, or T-Mobile is it is unlocked. I assume 911 would still work via satellite even without a subscription, but I guess I do Not know that for a fact.
Beyond that, you probably are looking at satellite phones, SPOT satellite messenger, and/or amateur radios. There are lots of choices out there, but unfortunately you can't get all of them in one device!