I had Achilles tendon problem for months last winter and my podiatrist put me what I call a walking boot... don't know if it's teh same as what you're talking about.
It's a hard plastic base, with two metal posts (calf high), a foam liner (sort of like the ones in some insulated winter boots, and velcro straps that keep your foot/leg in the liner seated inbetween the metal posts. I was please that it was only about $90. Was fine to wear in winter. Would be hot in summer. The difference in height can make you feel like 'peg-leg sam'. More importantly the height difference causes different muscles to be used and can cause back problems.
I was in it for 3 months and lucked out. My back never bothered me adn I got so used to wearing it wasn't really any problem. (However, never had to wear it to bed as my doctor threatened, if I wasn't really careful.
Had to hot soak my feet every morning before I could walk (bone spurs too).
Found out everything is washable, but almost got to the point of buying a new one - to have one for 'dress'! The original one got pretty ratty looking. The velcro starts eatting the foam on liner.
While wearing this contraption, I saw a lady with what looked like a regular shoe with metal posts attached to instep and a leather strap at calf height. Looked like that might work out a whole lot better for summer wear, if one were stuck with long term use. However, I never got up enough nerve to ask about it.
Hope this helps a little. If you neeed, I can get phone # for my podiatrist if you'd like to track down teh source.
Good luck. Tory in SE Missouri