The Sabayon Foundation has just had an official sub-license granted for our use of Linux(R) as part of "Sabayon Linux" & "SabayonLinux", covering goods and services on every corner of the planet (including Antarctica!).
Linux is of course a trademark of Linus Torvalds and the Linux Foundation can provide everyone who uses the trademark as part of their product with a license to use it in countries where it is trademarked. This is a good deal for everyone involved as it means that Company X can no go using the Linux name for crappy products and services.
And so Linux(R) License No. 20110410-0332 is for Sabayon.
I feel that I should mention a video by Jon "maddog" Hall, of his keynote at CeBIT earlier this year called "The Hidden Costs of Closed Source Software", the start of of which originally raised to fact that we had not in fact registered our use of Linux! Its a very interesting video and Maddog puts his points across fairly without going to GNUCrazy...