I hope you can see the ridiculousness is saying that corporations should be limited in wealth as well, but even if you can't, let's assume they are limited the same. Now it becomes easier to buy them off, because they are comparably smaller.
The only logical solution is to allow both corporations and individuals to accumulate as much wealth as they are able to. Rich people aren't the problem, corrupt people are. Instead of trying to make rich corrupt people less rich, why don't we try to make them less corrupt instead?