I'm not a fan of posting links to products, but just had to share this one with you, because I buy most of my heels online, and I have to send back about 2/3 because they don't fit right, or I can tell they'd be a pain in the... ...foot!
I came across this site a couple weeks back and ordered a pair of insolias, installing them in one of my favorite heels (for their looks). Unfortunately they weren't all that comfortable so I didn't wear them much. At first I didn't think it would work, as it's not a full-foot orthotic. But after wearing them around the house for a while, I realized my feet didn't hurt wearing them like they normally did.
Hooray!
So I wore them all day!
Here's the link:
http://www.insolia.com/index.html