Well, I got a hold of some of these. I convinced a distributor to send me a sample - and they sent me both a small and a large (I'd only asked for a small).
All I can say is, I'm glad I didn't spend any money on it. The large would fit about 3 of me, but the small is actually a pretty good fit around the legs. The sides, though, are incredibly puffy and thick, and the snaps don't align well (they're too close together on the front, as opposed to the back), so you end up with a huge fold that just makes it even thicker. It would be impossible to wear one of these without someone noticing. Also, the front of the diaper is almost comically higher then the back, so that you have to fold it down inside itself. The front unfolded was well past my belly button, while the back barely covered my butt crack =\ i think maybe the front is intended to be folded down, to help hold a booster in place, but that'd really only be useful for guys.
I decided to give it a try anyway, though, since I really wanted something for overnight.
I was wearing it for about an hour, and hadn't gone to bed yet, and the leg gathers were so thick that they actually started hurting my legs. Still not a deal-breaker for me, since again, I really wanted something for overnights, and the gathers aren't an issue when laying down or on your side.
On the plus side, they're very absorbent, and whatever rayon/polyester/whatever liner it has actually did a really good job of wicking away from the skin. Two (small) wettings in, I couldn't even tell it was wet. The gathers worked well, and overnight there wasn't any leaking from the sides. I decided to give the already-wet one a chance overnight.
The problem? They're not waterproof. There was no leaking from the gathers, or the waistband, but apparently, after a few hours, it leaks through the outer cover. So, I'd need to use plastic pants with them.
My whole reason for wanting to try something new, was in the (apparently vain) hope that I could find something that didn't involve plastic pants, since I wear them all day, too, and they tend to irritate my legs at the gathers when I don't give myself any time without them.
When I woke up, my bed was wet. Not soaked, the diaper held most of it, but that seeping through the diaper was enough that I was doing laundry first thing in the morning =\
Anyway, don't buy these

I'm seriously thinking about giving underjams a try. Does anyone know what their capacity is? Overnight, I wouldn't need more then 15 ounces or so. And they're incredibly cute

My dad will laugh at me for trying kid diapers, but at this point I don't care, as long as they work!