You're not probably going to find many dedicated road pedals/cleats which are conducive to walking. I know you said that it's personal preference, but I can't quite get on board with the statement that float is making your stroke sloppy. That is strictly a function of your technique. If float caused sloppiness you wouldn't see professional and other high-level cyclists on Speedplays, for instance.

If SPD doesn't give you problems then why not go with that? There are literally hundreds of different walkable shoes out there for that cleat and you will get rid of the float you said you didn't want anymore. When people go to road shoes over mountain shoes, it's usually because they want the benefits of them (light weight, stiff soles, they look cool), not the other way around.