Avram notes that the introduction of a product to the real world based on one from the fictional world is nothing new, citing Holiday Inn hotel and Bubba Gump restaurant chains as examples. While he's coined the term "tlönian" for this phenomenon, based on the Borges story "Tlön, Uqbar, Orbis Tertius," a commenter suggests "defictionalization," a Google search of which currently places the Making Light discussion as the #2 result, so I'm thinking it has staying power.
Other notable examples of defictionalization: the Red Swingline stapler from "Office Space" (1999) (another Mike Judge movie!), the Buzz Rickson's MA-1, made in black only after William Gibson wrote it that way in "Pattern Recognition," and of course, Spinal Tap.
A Tap-related Polymer Records t-shirt is available at Last Exit To Nowhere, where fine defictionalized goods are sold. I'd wear it just to channel Paul Schaffer's Artie Fufkin as frequently as possible.
And to the snackfood and energy bar manufacturers out there: who among you has the temerity to sell me some Soylent Green?