Hey, cnich007. You are not the first to come up with the idea, and that means that these sites are already familiar with strategies like you describe. For example, see this article from 2008 about Digg addressing group voting.
Digg cracks down on group voting
The simple problem with your scenario is that it creates an unnatural pattern of voting by the same people over and over. Any time you considered manipulating/gaming a system you should realize they have an enormous amount of data to establish what is normal.
Is this something most forums would say "NO WAY" to it's members doing??
Probably, most forums are not going to want to have their reputation associated with "gaming" another site.
Two cents ... spend your time working on quality content and your creativity and efforts will be better spent versus trying to figure out how to get ahead by scheming the system. In the end, something that games the system will eventually lose out where as if you do things "right" it will work for the long run.