Aeronaut - answers while waiting for the smaller-size model
OK, I broke down and ordered a regular sized model of the Aeronaut, even though I am waiting for the smaller-sized model, too (grin). (I can just imagine that they sell out, and there is another 3-month wait to restock! I figure that I can always give this to my sister as a present).
I think the bag will not be prone to overstuffing. The curved line of the seam (on the back view) and the other lines mean that this isn't a typical block design -- when you fill the bag the lines of tension go in a direction to hold the shape fairly well. Similarly, the interior side panels and snaps (which you can't see, since there are no photos showing this in the reviews or on the site) tend to hold the inside shape. This design is less constricting, however.
The same non-standard design lines mean that the bag also holds its shape when empty (or underfilled) better than you might think. There's a slightly diagonal component to the forces pulling in from the corners, and the curved lines on the two sides (see especially views 3 and 6 of the back and 4 of the end panels in the detailed view options on the product page) hold this in shape, while also giving a better curved fit to your back (view 5). (I realize this isn't a very well-done description, but you probably are more interested in getting an immediate reply that can be refined.)
Having tried on the back-pack, I can believe that the smaller sized "harness" will be more comfortable for a smaller build, although this is not bad. It's mainly that the width between the shoulder straps can't really be adjusted to any large extent and match as well to body size. YMMV. (I'm 5'4", and the usual problem I've seen with backpack designs is that they seem to be designed for guys who are much bigger and with broad backs).
Aeronaut Usage Comments and Questions
Yes, I meant to say "ballistic nylon" instead of cordura -- a residual side effect of mentally composing a response for a Buzz post, too. Here's a thread containing Tom's discussion of ballistic nylon and another thread with comments on recent cordura fabric.
The use of ballistic nylon really does help to provide a light-weight solution to maintaining the structure of the Aeronaut while removing the need for a supporting frame. Pictures of the bag for the product description should also include a shot of the Aeronaut opened and empty. The squarish "U" of the zipper actually provides a kind of reinforcing structure, and the stiffness of the ballistic nylon on the side (what would be the "bottom" of the bag when held by the handles) combined with the curved rather than squarish seam join at its base, results in the main compartment staying open and maintaining its depth while you pack.
The bag also gets structural support on the sides by the seaming and zipper designs of the side pockets. The curved seam designs are an inspired feature; not only do they work structurally for the support of the bag, but I'm pretty sure that for the backpack use they help the contouring to fit more comfortably to the shape of the user's back. On the sides of the bag, you can see that the hand pulls echo the shape of the curved seam design. This makes for a comfortable grip as well as being an aesthetic feature. At the same time, having the ends of the pulls attach to curved side seams makes pulling the bag out from storage easier, while I'll bet that it also makes it less likely that the seams will pull apart there due to wear. Very, very nice.
The main trade-off for the Aeronaut design seems to be in easy access to large size reading materials, although the side-zipped pouch works very well for even standard sized books, and newspapers, magazines, and brochures also fit in easily. I think that as a result of prioritizing light weight and good structural design, the kinds of large outside pockets for papers, etc. that you find on other carryons bags aren't there. So the Aeronaut's side pockets handle this instead. If you're carrying another personal carryon for your laptop, you'd probably access large papers and files from that bag. I wonder if there's an easier way to access airline/railroad tickets, though, since the side pocket with the diagonal zipper is multi-purpose, and a bit too deep to handle this easily.
I think the main potential problem area for overstuffing may be this diagonally-zipped side pocket (as opposed to the deeper pocket behind it), since it's relatively shallow, and backed with 200 denier nylon lining. If you were to consistently overstuff it with bulky items, like too-large water bottles, there might be consequences for the back lining.
I had a final question for the Tom Bihn folks about the rubberized zippers. I like this feature a lot, but I notice that the texture is a kind of matte black instead of the shinier and thicker rubber on the zipper of my Buzz. I haven't had any problems with that design on my (early model) Buzz, but I saw this thread about some eventual wear on the rubberized edges of the zippers, and wondered whether this was a newer design in response to this.
Oh, and people who have started traveling with their Aeronauts, are you using the zippered pocket that holds the straps for other storage, and if so, what do you put there? I imagine it could be used to hold folders and large flat magazines, but might be less comfortable to carry in "backpack mode".