I generally have concerns about looking too tactical, particularly in an emergency. Joe Average is too likely to mistake you for a cop; cops are more likely to think you are up to no good. And when the Guard comes in, yeah, that's a risk I'd like to minimize. Nothing against Gaurdsmen, but they aren't cops and a lot of them are pretty tightly wound, it makes the odds interesting.
That being said, if you don't go with camo or black, and you don't have a ton of little pouches, you will be in a better position. Unfortunately, they don't make a lot of MOLLE gear in crowd friendly colors, other than a few navy blue items over at Emdom and a few red/orange items of unknown quality that Major's Surplus or Sportmans Guide might have. So I'd recommend solid green or tan/coyote. Try to color match your pouches as well as you can.
My ditch kit, which is part of BOB, is
here . I use a two-piece MAV, which is much more comfortable than the one-peice MAV that I started with. My way of testing how a load rides is to go to my folks or up to a friend's place, both of which are on relatively minor roads, put them on, and take a four mile walk. When I started, I had a bunch of smaller pockets on the MAV-1. There must have been something karmic, becuase I saw more cops on those roads when I was testing that configuration than I've ever seen. And most of the cops slowed down or stopped. Nothing major, they were curious and thought it was kinda cool when I showed them what I was testing. But take it off a back road with a lot of stressed out people, and it isn't as pleasant a situation.
As it is now, I've been passed by cops on the same roads, and they just ignore it; it's also been seen by various people on foot, and they ask were my fishing pole is. (I tell them it is a telescoping one in my pouch if they are my parent's more dingy neighbors, or most of the truth.) So, I would say solid neutral color and big pockets are good. I've used patches with velcro in the past, but I'm thinking I'll see if I can find a second hand fleece lined vest or something, and make fleece patches for it so it really looks like a fishing vest when the time comes.
Now, I guess my question is, how much gear is in your BOB? I like this guy, becuase if this is all I have or I'm using the small school pack I keep in my car, I can wear it like a lumbar pack. But it is only a chest rig- if I need more stuff, I need a real pack.
If you are thinking something bigger than this, and you don't mind the price, how about the Camelbak Delta-5 vest? That gives you a 100 ounce bladder right off the get go. And it has enough space for 2, possibly 3 with a belt, buttpacks like the CountyComm EOD bags I used or the Emdom Wideload/Fatty Wideload on the back, and one more low on the front on each side, with a smaller pouch (like the MOLLE canteen pouch or the SpecOps X-6) higher up. Downside is that you start getting into real money for your nylon and you haven't added anything useful yet. Just keep in mind that you are going to look like you've gained about two hundred pounds.
I have a friend who is doing something like this with a vest made on a modified LBV-88 pattern but set up for MOLLE, and he's able to get most of a packload into it except for a real tent or sleeping bag, but he has rolled up wool blanket and tarp attached to it.
Another option might be a hunter's vest. Think the photographer vest, but with bigger (but fewer) pockets. A lot of them are set up with shotshell loops, which you might not want, but Eagle Industries makes a very nice hunters vest that used to be available in orange and red years and years ago. I know they are popular with game wardens so I can't image they've gone out of production.
