I've gotten Sam in 1/4 kegs before, and Wachusett in 1/2 barrels only. I don't know about Bud or Miller. Check out Berkshire -- I'm pretty sure you can get 1/6 barrels of all of their beers.
Sam Adams does tons of 1/6 kegs. I'm going to highly doubt you'll find Bud/Miller/Coors in 1/6 kegs. I'd imagine the smallest they would come is 1/4's... unless you count Blue Moon. That comes in sixtels.
I believe Berkshire does sixtels if you are looking for some NE craft. The Czech pilsener is in season.
Berkshire and Wormtown both definitely do sixtels. My first keg after getting my kegerator was a Berkshire Pale Ale.
Craft Beer Cellar posted a list of 1/6 barrels they can usually get their hands about a month ago: 1/6 Barrels 21st Amendment Bitter American Pale, Back in Black, & Brew Free or Die IPA Allagash White Allagash Dubbel Allagash Tripel Alltech Kentucky Bourbon Ale Atwater Vanilla Java Porter Avery IPA, White Rascal (Witbier), & Ellie's Brown Ballast Point Big Eye IPA Bar Harbor Blueberry Baxter Amber Road, Pamola Pale, and Stowaway IPA Bear Republic Racer5 IPA & Hop Rod Rye Berkshire Coffeehouse & Drayman's Porter, Gold Spike, Lost Sailor IPA, Steel Rail & Traditional Blue Hills Black Hops, IPA, & Imperial Red IPA Blue Point Hoptical Illusion IPA & Toasted Lager (Vienna-style) Breckenridge Oatmeal Stout & Vanilla Porter Brooklyn Brown, EIPA, Lager, & Pils Cisco Grey Lady (Witbier), Whale's Tale Pale Ale, & Sankaty Light Clown Shoes Clementine, Hoppy Feet, Eagle Claw Fist, & Tramp Stamp Firestone Walker Walker's Reserve Porter Flying Dog Doggie Style Pale Ale Founders Centennial IPA Geary's Pale Ale Geary's Hampshire Special Ale Geary's London Porter Great Divide HOSS Rye Lager, DPA, Titan IPA, & Hercules DIPA Harpoon IPA Harpoon UFO (Hefe) & UFO White (Witbier) Haverhill Cream Ale, APA, Leatherlips IPA, & Whittier White Heavy Seas Loose Cannon IPA Ipswich Ale (English Pale Ale) Jack's Abby Jabby Brau and Smoke & Dagger Long Trail IPA Magic Hat #9 Magic Hat Circus Boy (American Wheat) McNeil's Firehouse Amber & Dead Horse IPA North Coast Red Seal & Old Rasputin (RIS) Notch Pils & Saison Offshore Amber, Nut Brown, & IPA Ommegang BPA (Belgian Pale) Ommegang Hennepin (Saison) Ommegang Abbey Ale (Dubbel) Ommegang Three Philosophers (Quad) OPA OPA IPA, Red Rock Amber, & Blueberry Lager Oskar Blues Dale's Pale Ale & Deviant Dales IPA Peak Pale Ale & Nut Brown *Pretty Things Baby Tree (Quad) *Pretty Things Jack d'Or (Saison) *Pretty Things St. Botolph's Town (English Brown) Pyramid Thunderhead IPA & Hefeweizen Samuel Adams Lager, Latitude 48 IPA, & Cherry Wheat Sierra Nevada Pale Ale Sierra Nevada Torpedo Slumbrew Flagraiser IPA Slumbrew Happy Sol Slumbrew Porter Square Porter Smuttynose Big A IPA Smuttynose IPA Smuttynose Old Brown Dog Smuttynsoe Robust Porter Smuttynose Shoal's Pale Ale Southern Tier IPA, UnEarthly IPA, & 2XIPA Stone IPA Stone Ruination IPA Stone Arrogant Bastard Troegs DreamWeaver Wheat (Hefe) Troegs HopBack Amber Troegs JavaHead Stout Troegs Pale Ale Troegs Troegenator (Doublebock) Uinta Double Detour IPA Wachusett Blueberry Wachusett Country (Pale Ale) Wachusett Green Monsta' IPA Woodstock Pig's Ear Brown Wormtown Be Hoppy IPA
*disclaimer* The following is for Boston only and may vary by distributor in different areas The big companies come in 1/2 bbls and 1/4 bbls. Budweiser used to sell beer balls (party balls), which were essentially the same size as 1/6 bbls, but they were recently discontinued (much to the chagrin of anyone who purchased a beer ball tap)...but they wouldn't be of much use in a kegerator. Sam Adams comes in all three sizes, though not every beer comes in each size. Boston Lager and the seasonals definitely come in all three, including 1/6 bbls. Wachusett comes in 1/2 bbls and 1/6 bbls, at least the blueberry. Looks like Larry comes in 1/2 bbls only. If you're looking for an example of what kegs some of the bigger liquor stores that sell a lot of kegs carry week to week (and not just special orders), Blanchard's Allston has a large selection and the website was recently updated. Scroll down to 1/6 bbls, but the list doesn't include the seasonals. Most of the larger liquor stores will also order and hold any of the kegs from kinopio's list.
