Originally posted by McHack
I'm curious why you'd WANT to do this... After all, didn't the 35" scales rollout, as a mechanism for fixing B-String slop on 5-stringers?
Without the B string, there's no need.
Although some people will argue against this, longer scale will equal better tone and string response due to higher tension.
34" has become the generally accepted norm because that's what Fender ultimately went with. If a 50" scale Bass Guitar was practical/comfortable to play, we'd have a lot of 50" scale bass guitars (and this same debate when the first 51" bass came along

) once people heard the tonal difference.
34" was a compromise between the guitar's (about 27") scale and a 3/4 upright bass' (about 41") since Leo (Fender) was trying to market his electric bass to guitar players so they could increase their work oportunities. He would have liked a longer scale (he did try 36") but decided it would be too much for guitarists used to a much shorted scale, not because the tone wasn't better.
It's like the trade-off many upright, especially Jazz players, make in using a 3/4 upright over a full 4/4 instrument. On average, all things being equal a 4/4 instrument will have better tone, but the 3/4 instrument is much easier to play and deal with.
Anthony Jackson has recently lamented having to go from a 36" scale on his signature Fodera to a new 34" scale Fodera (due to a hand injury). Although he's confident Vinnie Fodera will be able to build him a great instrument at 34" scale, he does realize that it won't be quite as good.
34" scale will always have it's own characteristics (and thus, it's fans), but I've played and owned several 35" scale instruments at this point and the tonal difference (using the same strings, same gauges, just longer scale) is very obvious (to me anyway

).