Linkster, radar

I also believe that Google could check your NS1 NS2 etc...
And I've seen emails from hosting companies who have checked through our portfolio pages and informed us that all the customer sites are on very different IP addresses...... and how it would cost us less to move everything together on a big dedicated machine with them.
In the words of Jake Blues, when Elwood asked him to go and see the Penguin....... "No fucking way!"
Best way IMO is to start new sites on fresh IPs with Candid or Blue Gravity et al.... then if the site becomes busy and works up the engines, buy it some space on it's own.
Another reason for having separate IPs is when link list / tgp owners are banning your ass and do a reverse .......... I've said too much already.