The brands that reappeared in the 30 minutes search:
A- Adobe, Apple. Tons of Apple brand tattoos. Apple may rival our entry at "H" for top spot.
B- BMW, Budweiser, Burger King.
C- Coca-Cola, Cherry Coke, Campbell's Soup, Coppertone, Corvette, Chanel, Cisco.
D- Disney and Dr. Pepper.
E- Ed Hardy, Eggo. Eggo, who would have thought that?
F- Ford, Fender, Ferrari.
H- Harley Davidson. No surprise here given its cult status and target market.
I- Ikea. (Maybe you put it on yourself?)
J- Jack Daniels. These tend to be large tattoos. Joe Camel is still popular
K- Kool Aid (There really is a cult of the Kool-Aid man.)
L- Louis Vuitton.
M- Microsoft, Mustang.
O- Olympics, Oakley and Oreo. Olympic rings are common among athletes, as expected.
P- Pillsbury Dough Boy, Playboy, Pepsi.
Q- Quaker.Somehow tattoos don't suit the clean-cut wholesome image of a company that got a good start with oatmeal.
R- Reese's and Red Bull.
T- Tim Horton's, Triumph.
V- Verizon, Versace and Volkswagon.
W- Wikipedia, Wendy's and Wal-Mart.
X- X Box. (I didn't find Xerox!)