I would imagine you could setup a macro on firefox for this.
Maybe something in conjunction a hide ip address software, or using a proxy.
It would also help if you knew the keywords you rank for.
So the macro would:
- Change IP Address
- Go to google.com
- search for keyword
- click on your site's link
- visit the site for a certain amount of time
Then repeat.
This would show a bunch of different ips coming from google.
I am not a "macro" sort of guy, but have done it a few times to fake the crap out of squidoo to get my sites in the top 1000