The earliest 2x3 Graphic was the Miniature Speed Graphic, made from 1938 to 1946. It was replaced in 1947 by the 2x3 Pacemaker Speed Graphic (has a focal plane shutter) and and 2x3 Pacemaker Crown Graphic (no focal plane shutter, shorter body). The Century Graphic (essentially a 2x3 Crown with plastic body) as added to the line in 1949.
Since you're interested in using short lenses, 2x3 Graphics' minimum flange-to-film distances are: Mini Speed, 58.7 mm; Pacemaker Speed, 61.9 mm; Crown and Century, 34.9 mm. Other pros/cons? The big one is that some, not all, say that the Mini Speed's shutter cloth is less durable than the 2x3 Pacemaker Speed's.
The shortest easily-found lens that will make infinity on a 2x3 Speed is the 58/5.6 Grandagon. The shortest hard-to-find lens that will make infinity on a 2x3 Speed is the 1.75"/2.8 Elcan. The shortest lens that will make infinity on a 2x3 Crown/Century is the 35/4.5 Apo-Grandagon; this is also the shortest lens that covers 2x3. The 1.75" Elcan covers, if you can call it covering, at most nominal 6x7. If you want to shoot lenses shorter than 65 mm you want a Crown or a Century.
You can read more about these and other lenses on 2x3 Graphics at
http://www.galerie-photo.com/telechargement/dan-fromm-6x9-lenses-v2-2011-03-29.pdf . Don't nod your head, download it and read it. Also visit
www.graflex.org and read the FAQs.
Graflex' nomenclature confuses everyone. 22 and RH-12 rollholders are for 12 nominal 6x6 exposures on 120 film; RH-10 for 10 6x7s; 23 and RH-8 for 8 6x9 (really 2.25" x 3.25", 6x9 is a poor metric approximation).
Lens in barrel or in shutter? Speed Graphics have focal plane shutters, can use lenses in barrel and in shutter. Crown/Century have no focal plane shutter, can use only lenses in shutter.
Um, y'r equivalence factors are wrong. The 35 mm still frame is 24 mm x 36 mm, diagonal 43 mm. The nominal 6x9 frame is 57 mm x 78 - 82 mm (roll holders vary, some 6x9 fixed lens cameras have gates as long as 85 mm), diagonal 100 mm. So a 65 mm on a 2x3 Graphic with a 2x3 roll holder sees the same view as a 28 mm lens on 35 mm still. There's only one 50 mm lens for 2x3, it is in the Mamiya Press system. Uncommon, expensive. A 47 mm Super Angulon is probably a better proposition.
Dark slides? Roll holders ship with dark slides, they're unusable without one. Dark slides are lost. The least expensive source of replacement dark slides for Graflex roll holders that fit 2x3 cameras is Graflex 2x3 film pack adapters.