Multiple domains <-> cross linking.

[Herath]

We have 4 domain names mapping to the same site. (ie. foo.us, foo.info, foo.net
all mapping to foo.com)

All these domains map to a single IP, so google knows they are the same.

We are now looking at creating 4 seperate sites(different content) and distribute these domain
names amoung 4 unique IPs. (So we can cross link and possibly appear on
google's result pages several times for the same keyword).

Any suggestions, thoughts on this?.

[troels nybo nielsen]

Sounds like you have thought it well out. But be carefull. In some people's eyes a construction like that might look like spamming, especially if those websites are commercial and have competitors. They might report you to Google and someone from Google might take a look.

So be carefull to build good content, a nice, clean design and a natural and user friendly linking structure.