Closest thing I can think of on MD is the spinning ship animation on the high score screen of Subterrania, it's ultra smooth.
I think we can all agree Rendering Ranger would have looked far better with the pixel art Trenz was originally planning for the game. As far as the game itself, I still haven't played it but I have heard the level design is a bit flat in comparison to some of the SNES's heavy hitters.
OT: Kentosama, IRENA Genesis Metal Fury (can't argue with the name) is obviously in an embryonic state atm; I think joining up with shmups.system11.org and heading over to the dev forum could help if you haven't already done so.
Have you considered what sort of gimmick the game's system could use to give it a unique angle? Something as simple as vacuuming in gems from killing mid-size enemies, building a gauge that maxes out for a smart bomb or hyper beam type over weapon perhaps.