x

[Shambala Kimono]

x

[Rolig Loon]

Not possible except for some RL corporations, which can apparently set up blocks of avatar names that identify them with the corporation (like Sally.IBM, Bob.IBM, Pedro.IBM).

[Malarwen Hall]

Yes, it is possilbe, however, it is also very expensive. $500 set up fee and then $500 annual fee (note that the price is in US Dollars, not Linden Dollars)

Also, your last name must sound like an organization - LL used to provide pretty much any custom name but that's not longer an option unless you are best buddy with some higher up Lindens.

Official info is here: http://wiki.secondlife.com/wiki/Linden_Lab_Official:Custom_Name_Program