Most guitars, including jazz guitars, are factory made. The most renowned names are: Gibson, Guild, Gretsch and Ibanez. Many guitarists prefer to play guitars built by luthiers. These can either be standard types, with or without custom options, or completely custom built guitars. The standard is the 6-string, but the last 20 years or so, more and more jazz players prefer the play a 7-string guitar with the so-called “Van Eps”-tuning, with an added low A 7th string.
The same goes for guitar amps. The majority of jazz players still use e.g. a Fender combo amp, but at the same time the marked is flooded by “boutique” style amps. Small and easy to carry amps, like: Gallien-Krueger, Acoustic Image, Mambo Amp, Henriksen "The Bud" and so far the two lightest, the Quilter 8 and the "DV Little Jazz" make getting to and from the gig so much easier these days!