I preface this with the statement that all my comments are in regards to Alembic basses. Your experience with other maker's products may be different, and probably is.
We have made short scale 5 and 6 string basses with short scales. These were for customers who well knew what to expect. Sure, it's going to be looser feeling than a longer scale. Somewhere out there, lives a Stanley Clarke Deluxe 6-string short scale with a Purpleheart and Vermilion neck. This was in the days before I took thousands of pictures, so I don't have any photographic record of it.
When someone I don't really know well approaches us to get a short scale 5-string bass, I invite them to string up a 4-string short scale Alembic BEAD. Even without intonating the bridge or having the perfect setup, you'll be able to tell if the feel of the B string will bother you enough to interfere with the music.
What I don't think we'll make any more of is a Small Standard body with 5- or 6-strings. It just doesn't really work out for balance.
Scale length is not the sole determining factor for good tone from a B string. Shorter scale basses get a bit of prejudicial treatment since some of the medium and short scale basses of the 60's weren't particularly great sounding. I don't think these would magically transform into wonderful sounding instruments if you put a longer neck on them. Materials, quality of construction, strings and setup play a huge role. And then of course, there is the talent and skill of the player.
And while I can confidently say you will always feel a mechanical difference with different scale lengths, it's not always true you will hear a difference that you can attribute to the scale length on an Alembic bass, especially comparing 34 to 35 when listening only.
One of the best reasons to get a 34 scale 5-string is that you'll have the largest selection of available strings. Pickins aren't slim in the 35 aisle either, but you'll have more choice available to you in standard long scale. And in my experience, one of the single most powerful tone controls you've got on an Alembic bass is the choice of strings. Changing the strings can make it sounds like a whole new bass.