Felixous - 1 hit in Google from a web page that doesn't contain it.
Felixio - 5 hits, none look relevant.
Felixosgi (or Felix-osgi) - no hits.
My favorites
Felixfur - no google hits.
Felixcatus - only a few - none look relevant.
If you want to vary a bit:
Felion
Chausie (this one will get you an O'Reilly book since it is a real cat
breed). See http://www.catfancy.com/catfancy/Breed_Profiles.aspx?aid=5979
FelisChaus (the latin version of the above).
Sylvain Wallez wrote:
And what about variations around Felix that for sure would have no
trademark strings and would be more "google-friendly"?
Felixo, Felixi, Ofelix, Felixa, etc.
Sylvain