The amount of memory has nothing (well, not much) to do with 3D. The whole mantra of "more video memory is good" is ONLY for textures. You can do a simple raycaster with very little memory. There *are* simple 3D demos already out there. Granted, you can't get much detail on the calculator, so really there isn't much point.
no, a 3D zelda would probably be just link s head at the bottom of the screen and as you turn, so does everyting else (like a downward angled FPS) and one level grey IS enough detail to work decently (at least if it was using 8X8/ 16X16 sprites, each with four directions and all...basicaly Link's awakening sprites that scale and draw via ray casting)
First of all, texturing a large portion of the screen is halfway to hell. Second, determining what to render is beyond hell. Zelda games play in pretty "organic" environments, so 3D is not an option on the calc. Stick to tilemaps, they can be pretty
Link's Awakening is okay but I prefer Link to the Past . Just got me ticked off when I found out the ending of LA...wth all this questing and stuff was a...
Projects:
Phantasy Star Dark Millenia - Put aside for the moment...
because Zelda require a quite large amount of CPU time to handle attacks, enemy attacks, magic, enemies themself and many othe rthings, which slow down the game a lot.