MILWAUKEE — In a little shop on an unassuming block, Josh Wright sells some of the prettiest, priciest electric guitars you never heard of.

Fender? Gibson? There are some, but for the most part the walls at Distinctive Guitar are hung with the work of small builders, such as Joe Knaggs or Tom Anderson, who turn out a relative handful of instruments.

The market for these guitars, most of them priced between $3,000 and $7,000, is narrow. But it has been growing, thanks in large part to aging baby boomers who grew up on the Beatles and Stones and Led Zeppelin and now have the money to afford a fancy ax.

“That’s precisely it,” said Brad Tolinski, editor-in-chief of Guitar Aficionado, a magazine launched six years ago in response to the trend. “It’s the rock ’n’ roll generation.”

Started as an online business by Wright, a former equities trader for an Evanston, Illinois, investment firm, Distinctive Guitar opened its shop here — cheaper rent and less competition than in Chicago — in late 2013. Most sales come from online traffic, but some guitar builders require dealers to have a brick-and-mortar store, said Noah Saydel, who runs the shop and is the firm’s marketing manager.

And while one might think the customer base leans heavily toward working musicians who appreciate the subtleties of fingerboard radius and humbucker pickups, that’s not the case.

“Most of the time it’s business professionals,” Saydel said. “The average musician just kind of looks for workhorse guitars, whereas most of our customers are doctors, lawyers, stuff like that. Or collectors. The musicians come in and appreciate them and then the doctors and lawyers come in and buy them.”

The market they and others have created for boutique guitars, many of them custom-made for the individual buyer, has taken off over the last decade.

“I noticed a serious uptick maybe about 10 years ago, then very seriously over the last maybe five years,” said Tolinski, who also edits Guitar World magazine.

Others in the industry agreed.

“It’s definitely like a big boom time of these small builders,” said dealer Wes Bentley, who owns Rebel Guitars in Sylacauga, Alabama.