could you get the condo board or HOA to CREATE rules governing this?

You'll get all the downstairs neighbors voting yes, and allt he upstairs neighbors voting no.

The only other possibility is to politely ask them not to wear shoes--that would help a bit.

That's horrible. Talley Sue has a point - maybe you could get the rule for this in effect. To be honest, don't know how much they would enforce it, though. We have a rule in our co-op that all floors must be covered in carpet, excepting the kitchen and bathroom. Our upstairs neighbors sound like they have elephants in their apartment. We know for a fact that not only has the super seen their apartment but also one of the members of the Board. And still they plod along at 4:00 in the morning. Can't seem to win.