Does anyone know if any brands of guitalele come already tuned in guitar E tuning instead of A tuning?
In my experience the shortest scale you will find whereby you can reasonably tune EADGBE and have proper tension and string mass for useful intonation is a 23" scale or sometimes referred to as "7/8 scale" or "3/4 scale".
Most guitalele/guilele/kiku are baritone (19-21")or tenor (17") scale.
On my Cordoba Mini, the lowest TUNING I was comfortable with using high tension classical string (Thomastik-Infeld CF128, ~$19/set) was called "Terz' tuning, which is Italian for 'third' as in a 'minor third' higher than E.
This is an officially recognized tuning and there's tons of music written for this instrument, in the Renaissance, Baroque and 'Moderne' periods.
I have my Mini tuned as Terz, which is like tuning your tenor to F-Bb-D-G, but with 6 strings as G-C-F-Bb-D-G, and in my brain, I am playing and thinking in "E-tuning" as per the chord shapes, and since I am only writing my own music, I only have to worry about naming the chords or notes or whatever key I am in, if in fact I am writing parts for other instruments, otherwise I just dont think about Terz vs. "E-tuning" and only care about the SOUND of the music.
Aquila collaborated with Cordoba to make a set of strings in 'E-tuning' for the Cordoba Mini, but so many folks hated them, that I never bothered to try them myself.
ASIDE from all of the above, you also have to contend with the physics involved in that the body of a guitalele/guilele/kiku has to be LARGE enough to resonate those low frequencies of the 5th & 6th strings, otherwise it will sound either/and of very low volume and/or 'choked-off' and lifeless.
You cannot fight physics, and this is why an upright bass has a HUGE violin-shaped body, partly for the ability to resonate the low bass frequencies, and partly to have enough VOLUME to actually be heard without amplification, as part of an ensemble and taking advantage of the architectural acoustic properties of a concert hall designed for such music (classical).
Hope this helps!