If you decide against a concert or concert scale soprano, I can strongly recommend the Kiwaya KS-5 uke in Koa laminate. Very loud and barking!
I imported one of these from Japan (where they are called Famous KS-5) and it arrived just a couple days ago. I went with the G model (FS-5G) for the geared tuners, which is a bit of a compromise for me as they are lighter than planetary tuners, but heavier than friction tuners (I prefer sopranos to have a very light headstock, if possible).
Like Max said, the FS-5(G) is really loud, but it's a different kind of loud than my 1920s Lyon&Healy soprano (also loud, but in that 1920s way). The Famous/Kiwaya rings more clearly (or cleanly) with exceptional note separation. Just the right amount of sustain for me, too, not too little, but also not too much. It's as loud as many tenors, and louder than some. It does not at all sound like laminate. I was skeptical of laminate before, as those instruments tend to sound muted and boxy. This one does not, and to my ears it sounds better than most new solid wood sopranos under $1000 that I have heard. It plays well up the neck and doesn't get as quickly as thuddy as many sopranos when you go up. The saddle is heavily compensated, something I had never seen before in person (looks like a mountain range).
They do make a concert version of this, the FC-5. I considered it (still doing so), but I'm so impressed with the FS-5 that right now my need for an instrument that combines playability (the FS-5 has a wider nut, so wider spring spacing, and a nice, fast neck that is neither too thin nor too thick), volume, and bark is satisfied. I am really glad that it sounds so good, because I'm more comfortable with the low-maintenance requirements in terms of humidity and temperature of a laminated instrument. Peace of mind and all of that.
I also had a KoAloha longneck soprano (pineapple), which I sold a few weeks ago. It was a fine instrument also. I'd say a little quieter than the FS-5, but also far louder than the average ukulele (of any size) and it played well. It had the distinct KoAloha sound, which I sometimes experienced as a bit too "brash". Not in a bad way, really. It's really that specific KoAloha sound. The KS-5 has a different voice. I'd say it sings more, more crystalline heights (peaks) whereas the KoAloha had stronger, fuller, and as a result "duller" (wrong word, but not as needle-like heights as the FS-5 has). Both are fantastic instruments, it just depends on the sound you want. The KoAloha is much more Hawaiian sounding. Chime-y, that is what the FS-5 is!
