Shimano A530 (though I wouldn't say SPD has very good float)? I see you don't like the platform one side/clipless on the other, but how else will you get comfortable in regular shoes? Anyway after riding these for five minutes I don't even think about which side is which, it comes very naturally.
How far are you going in regular shoes? I've got Speedplay Zeros on my road bike and while not optimal, I can ride those as very small platforms if I'm just going down the street.
Edit: How about a clipless pedal with a platform adapter? I know they have them for SPD and Eggbeaters...