The best thing you could do is to get the bent rim fixed (while you're at it, check to see if any other wheel needs to be repaired), then take all of your wheels and have them rebalanced at a different shop. This shaking might be also bad for your suspension (like alignment), so if you could get a hold of a set of different wheels (that are balanced of course) and see if you could duplicate the same situation. If you don't experience the shaking with a different set of wheels, then it's your wheels that need to be rebalanced. Might want to look into getting hubcentric rings to see if that'll help alleviate the problem.