Manfred Klose wrote
"a wall of marshall's"
I really like that! A cool collective noun.
Here's a couple of "unofficial" collective nouns I've collected over the years (strange hobby, I know :-[)
An absence of waiters
An accompaniment of condiments
An amble of walkers
An annoyance of mobile phones
An anvil of blacksmiths
An archive of programmers
An assemblage of jigsaw puzzlers
An attitude of teenagers
An audit of accountants
A bank of circuits
A billow of smokers
A blaze of pyromaniacs
A body of pathologists
A bond of British secret agents
A brace of orthodontists
A buttload of proctologists
A camp of transvestites
A clench of sphincters
A clutch of auto mechanics
A collective of nouns
A crash of software
A dawn of morning glories
A desperation of divorcees
A disputation of lawyers
An embarrassment of parents
A flunk of students
A flood of plumbers
A fright of ghosts
A giggle of girls
A groan of puns
A gross of farts
A guilt of pleasures
A handful of palm readers
A harmony of singers
A huff of people who write letters to the editor
A jagger of tongues
A kettle of drums
A mass of Catholics
A number of mathematicians
A ponder of philosophers
A rhyme of poets
A rush of overnight couriers
A scale of ichthyologists
A slice of circumcisions
A snap of photographers
A Sousa of marching bands
A spread of nymphomaniacs
A stock of portfolio managers
A wave of surfers
A whored of prostitutes
A wiggle of Elvis impersonators
Now we need some more guitar related ones, like a plethora of plectra! ?