Rolf Spuler (born 1958) opened his first shop 'Gitarre-Stübli' in Winterthur, Switzerland  in 1981, where he repaired and made guitars. Collaboration with Matthias Grob led to the development of the the PPP (Polyphonic Piezo Pickup) and the Polysubbass.  In 1984 he opened Paradis Guitarworks with Matthias Grob and Iris Dressler - but Dressler soon left replaced by Jury Roten. In 1988 Spruler made the first prototype of his Avalon guitar design and it made its debut at the 1989 Frankfurt trade fair.

Rodeo Music Corporation of Beverly Hills, California registered the Rodeo brand name in 1964 for acoustic and electric guitars, ukuleles, guitar cases and guitar amplifiers. They had been using the Rodeo brand name since February 12, 1964. Rodeo guitars were made in Japan.

Source: Official Gazette of the United States Patent Office. Volume 810. January, 1965.

Rockoon was a Kawai brand made in Japan the late 1980s early 1990s.They typically had Schaller hardware and are often branded "Schaller Rockoon". According to the Kawai Rockoon 1992 catalog:

"Rockoon is a high performance guitar created by the skilled and uncompromised crafstmanship of KAWAI. We have always been innovating the ideas and designs to continue our tradition of making high quality musical instruments of the finest material for progressive players. Our advanced domestic manufacturing facility allows such concept alive and remains the same as the solid foundation of our creativity.

We keep the musicians' needs in mind, it will be the innovative impulse which makes ROCKOON continue to grow."

Source: Kawai Rockoon catalog. 1992

Rockit guitars were made by Rod McKenzie in Everett, Washington from around 2007 onwards. McKenzie had years of experience customizing and building cars and motorcycles and was inspired to make the Rockit electric guitar with a design based on a motorcycle gas tank. McKenzie's friends at the Gompf Brackets company lent their machine shop, tooling and CAD expertise to the project. Although the prototype was made from an actual gas tank the production Rockit guitar bodies were made of fibreglass (much lighter) and could be customised with hot-rod graphics, gold and silver inlays and diamond fret markers. They sold for around $5,000 to $7,000 each.

Source: Guitar maker on a roll. Herald Net. April 1, 2007.

A&F guitars was a short-lived partnership started in 2001 in Riverside, California by Fred Stuart and Alan Hamel previously of the Fender Custom Shop. A&F made a boutique electric guitar model called the Rock-it-tone based on a Stuart design done for the Fender Custom Shop - but rejected by them. They also sold A&F brand pickups designed by Hamel and made custom electric guitars to order. In 2003 they went their separate ways and founded Stuart Custom Guitars and Alan Hamel, both continuing to make basically the same products that A&F had been making.

Source: Audio tools.com: defunct musical instrument makers (2 December 2019)

RockBeach guitars are made by Greg Bogoshian in Rochester NY. Greg has been making guitars since 2004. RockBeach electric guitars typically have a chambered body with a shape inspired by the Holdsworth FatBoy.

Source: RockBeach Guitars website (29 November 2019)

Robson is a maker of hand made tuning machines for all types of guitars, mandolins and ukuleles. The company was founded by Keith Robson in the early 2000s and is based in the North East of England.

Source: Robson website (26 November, 2019)

Universal Audio was founded in 1958 by Bill Putnam Sr. as a maker of recording equipment. Putnam was the inventor of the modern recording console, the multi-band audio equalizer, and the vocal booth, and he was the first engineer to use artificial reverberation in commercial recording. Alongside his friend Les Paul, Putnam was also involved in the early development of stereophonic recording. Putnam started three audio product companies during his career: Universal Audio, Studio Electronics, and UREI. All three companies built equipment that remains widely used decades after their introduction, including the LA-2A and 1176 compressors, and the 610 tube recording console.