I strapped it on the bike quickly at the bike shop and sat in the saddle. No knee interference here with my short legs.

Being so wide, it may be a little less stable than the RD bag, so I wouldn't plan on filling it up with rocks or anything.

As I've been shopping for a top tube / gas tank bag for my mukluk, most that I find seem too small to really be worth it. As I was perusing the LBS today contemplating the purchase of the Revelate gas tank, I saw in the next rack over, the Lezyne XL Caddy: http://www.lezyne.com/en/xl-caddy

It's about the same height and length as the RD gas tank, but much wider! It has two velcro loops you could use to attach it to the top tube and two saddle rail loops that you'd have to jimmy around, but they would definitely work to hold it to the head tube. It has two small size pockets for misc small items. It seems to be about $5-10 cheaper than the RD gas tank, too, but made in China. =(

Anyone done anything like this before? Thoughts? I'm very very tempted by the idea.