A NexTag ad I saw on Yahoo today entices readers to "Earn a Degree in as Few as Two Years!"
How does this happen? Most likely, some copywriter wanted to write as "in as little as two years" then, half-remembering something a teacher had once said about "few" and "fewer" being more proper, decided to play it "safe."
"As little as two years" sounds better for a reason: It is better. "As few as two years" emphasizes years as two individual units. "As little as two years" suggests a span of time, which is probably what was intended. Besides, "as little as" is a well-known figure of speech (12.4 million Google hits) while "as few as" is less common (1.6 million hits) and therefore less natural sounding.
The lesson: Your ear is a usually better guide than some vague half-recollection of some supposed rule. The natural choice is often the best choice.