Well......
Great idea, we are always looking to add optional features which make it more useful for different scenarios. In v2.3 we added the ability to 'Only allow user to submit form one time', followed by a message you can set to display if they come back to submit the form (i.e. Thanks but you already submitted or in your case, sorry you already voted!).
Now as far as displaying results you can use Dynamic SQL Events to store the data into the quick polls tables directly (some research involved here though to get the right tables, columns, make sure its updating the right poll, etc...). This is possible but obviously more work then we are looking for here.
Ill have to think about this more, there are a few ideas I have but nothing I see as being the best solution yet (or one that we would want to put into the released version of Dynamic Forms at least).
-Chad