no small matter

My wife and I agree on nearly every matter of consequence, so our bitterest feuds are always about trivia. Last night we argued (discussed, debated) the accepted plural of the proper noun "Adidas." Consider the following sentences:

"I wore my Adidas because my Nikes were consumed by mold."

"I wore my Adidases because my Nikes were consumed by mold."

She argued that common usage supported the former; I argued that grammatical propriety supported the latter. Alas, we were stuck in the car, with no Google to guide us. When we arrived home, what was the first thing we did?

That's right.

Our research ended up meandering through some interesting and unexpected areas. First, we discovered that I was somewhat right; in published documents, "Adidases" is the preferred plural, while the vernacular favors "Adidas." However, trademark regulations say that both are out-of-bounds.

NEVER modify a trademark to the plural form. Instead, change the generic word from singular to plural.

EXAMPLES:

1. tic tac candies, NOT tic tacs
2. OREO cookies, NOT OREOS

Furthermore, we discovered that the warring bastions of the British press disagree over the proper capitalization of "adidas." The Guardian:

company names
use names the companies use themselves, except in cases where they adopt typographical or other devices that, in effect, turn them into logos
So: Adidas, not adidas; BhS (no italicised h); Live TV (not L!ve TV); Toys R Us (do not attempt to turn the R backwards); Yahoo! is OK

But contrast The Times:

adidas (l/c) policy is now to allow companies the styles they wish to follow. See AXA, BUPA, easyJet etc

Confounding expectations, the politically conservative Times is linguistically progressive, while its liberal twin stands against the changing tides of usage.

Now, a challenge: is there a word in the English language that ends in -as and is both singular and plural? (If you say "maracas," you're wrong; the singular is "maraca.")