I've been experimenting with a locally produced wipe on water based (poly) clear gloss. I've been diluting it slightly with demineralised water, and padding it on a la French Polishing. It dries very quickly making the technique bearable, and results in an attractive lustrous gloss with no extra finishing required. After two months of hardening, it seems reasonably durable and buffs out easily after being lightly gouged with a thumb nail. The thing that impresses me most, is that it is not particularly reflective, so that the grain is enhanced, but still looks natural. If a mirror finish is desired, then I'd say don't bother. It may be able to be buffed to a high gloss, but I suspect it will not be hard enough to maintain it.
When I (eventually) apply it to a finished instrument, I'll send it to the local ukulele group for field testing. If it's too soft to survive that treatment, I'll drop the idea.
I will not recommend the technique at this stage, but it seems to have promise. A commercial builder would have to be brave, reckless or both to implement this, but it should prove adequate for careful use.
Time will tell.