I guess the question should be who doesn't make 30" shafts. You don't see many from Pred, but they are out there as an option. I'm not sure of a maker that doesn't offer it as an option.
For me, it kept me from buying quite a few custom cues that were offered for sale with 2 standard length shafts. Just couldn't see buying two standard shafts that I would never use. I've bought my last two Jacoby's at their booths at state tmts by me partly because I liked the cue I saw, but also because I could change out the shaft the cue was displayed with for another of my choosing. Jacoby makes a very high quality cue