If every search is personalised then what does a personalisation-free search tell you? It's possible that it will no be closer to what most people see as very few people jump through the hoops you're jumping through.
It might even be less like the majority of search results.
But, I assume, the bulk of the search ranks will be the same for people in the same (advertising) target group. (I have nothing to back up that assumption - it just would be the most sensible thing to do, I think.)
Looks like an opening: have a group of users sorted across demographics that you can automatically send a query too. The system returns the SERPs from each user and compiles a master SERP showing position based on demographics of the user? So you can, say, run a search for "search engine" across 1000 user machines and then look at average placement (with variance) for Windows 7 users aged 30+ in USA, or whatever.
You could probably do a similar thing with Tor (or a botnet) but the relationship between the SERP data and the demographic of the user is probably the most pertinent information and that would be lost then.
Not to mention they would get some very strange things popping in Google Now! Oh, it's a tangled web we weave...