Exactly what length do you want? And what custom features? I lived in Hawaii for a few years long before there were good gun choices, but I think that Ulusub 145RH would be ideal. Take a look at some of Jon's videos taking 100 foot drops and shooting fish. If I didn't already own an Abellan that was almost identical in length and band stretch, I'd own that gun for California. If you think its too pricey, then I don't see how you expect to get a custom gun cheaper and it comes with two shafts. You could get one flopper and one threaded for slip tip, or two of either one. And BTW, two 14.5 mm bands are more than enough for a gun that size. Three would be way too much. The gun has a high AR-15 handle. Not quite as high as my Abellan, but higher than most. It has compartments fore and aft with lead disks so you can customize ballast and balance. In my case I like guns that barely float with the shaft in, and I was able to remove enough lead to make that happen.
Do you want a bigger gun? The Ulusub 155RH has three 14.5 bands and is a real beast. A friend just shot a 60 pound yellowtail with mine last week.
Since you seem to be on the Big Island, I'll mention a couple of other brands made there. KAP seems to be very popular, although the handle doesn't look to be mounted high. And old dive buddy of mine who moved to Oahu said that Maohi guns were highly regarded, so he ordered one last February. He had to pay up front and still doesn't have the gun. The owner, Jake Wong, keeps making excuses. The gun is at the engraver. It seems to have been there at least twice. He is caring for his sick mother, etc. He "hopes" to ship it by the end of September, but now it's October. Maybe his excuses are all valid and his mother is truly ill, but I wouldn't order a gun from him right now.