Carrying Photo Gear

I need a new camera bag. I've looked at numerous bags at a couple of different shops, but I've not found a bag that is quite right. I spent some time trying to figure out what features I would actually want in a bag and trying to analyze why I didn't like any of the bags I've seen. I now think the problem is that I have several different needs that don't mesh well. I have basically four different needs:

1. Simple hiking / skiing, where my Lowepro Slingshot works very well.



2. Walking to and from work, where my current pack is okay, but having a laptop holder would be nice.



3. Flying to other places, where I need to bring at least one laptop, and my Slingshot doesn't help and i end up bringing a backpack as well.



4. Location shoots, where I have my Slingshot, my small shoulder bag, and a baseball bat bag (for light stands), all completely full of equipment. My current setup would be fine if it weren't for the fact that I like to hike to remote locations for these shoots; the light bag is rather uncomfortable, and I'd prefer to not need to bring the shoulder bag.

Trying to satisfy all of these situations is too expensive, so I need to find a way to have a bag serve multiple purposes. Since my Slingshot works well enough for the first two, I'm focused on finding a good solution for the last two. Leaving the light stand carrying method aside, I think I have these requirements:

1. Large enough to carry my Nikon D80 (and maybe my Hasselblad 500C/M), along with a few flashes, and an extra lens or two.



2. Small enough to be a carry-on for air travel.



3. Able to carry a 15" laptop.



4. Easy to strap a water bottle to.

The biggest obstacle seems to be finding one that is versatile enough that I can use it to carry both photo and personal gear on an airplane, or photo and hiking gear when on the trail. There are plenty that do either of these very well, but none that accomplish both. I'm not suggesting that I know how to fix this dilemma, because I do not. Currently, I'm considering something like the Tamrac Adventure 10 (or maybe the slightly smaller "9") which has a nice large pouch above the camera compartment for holding non-photo gear, or the Tamrac Expedition 7x, which has more padded pockets for photo gear and no non-photo pocket, but does have better external straps to hold tripods, water bottles, and the like.

My last dilemma is how to carry my lighting stands into remote locations. For places I can easily drive to, the baseball bat bag works nicely, but carrying it several miles through mountain trails is quite uncomfortable. Perhaps I could buy an old frame pack and modify it to be able to hold the stands? More research must be done here.