"Esas camas son un poco pequeñas."
Translation:Those beds are a little small.
I may be trying to overcomplicate, but why shouldn't it be "unas pocas pequenas" to agree with the feminine plural noun camas?
There's no need to agree with anything in this case, because "un poco" is modifying the adjective "pequeñas". In this sentence "poco" is an adverb.
"Unlike Spanish adjectives, Spanish adverbs are invariable, which is a fancy way to say they do not change according to the gender or number. This is because adverbs modify verbs, adjectives and other adverbs, not nouns."