Chris Gilmour is a UK born artist currently living in Udine, Italy, who specialises in life size cardboard scupltures of everyday objects. His work includes three full size gibson style guitars: an ES-335, a single cutaway Jazz guitar and a flying V.
Chris claims his first large sculpture was a cardboard cow, “to sell to farmers in order to replace the cattle destroyed by BSE, so that the fields don’t look empty”.

If you want to try this yourself you could get some of the paper guitar templates enlarged and trace their outlines on cardboard.

Link: Chris Gilmour cardboard artist.