Originally Posted by
Loose Chain
Gears in the back on a 135mm axle, single crank up front and real brakes
My only comment would be, "Why bother?"
That's not meant as a snarky comment. Levers and calipers and shifters and cables and derailleurs kinda defeat the whole point of a cruiser. And since you are building a real bike, you might as well use a real frame. Especially since you already experience fit issues with cruiser frames.
If I were building a beach bike to fit your needs list, I'd use an old rigid steel MTB frame. Rear triangle already spaced properly, room for big tires, brake mounts, cable guides, etc.