yeah, the mario chip is the super fx. most copies of starfox have the chip labelled as "mario chip" on the pcb. its possible that they started developing it for the nes, but i've never heard of that before. i've read its patent before and it never mentions the nes, just the snes. unlike other patents, its pretty spot-on and describes the hardware accurately. before the official documentation became avaliable, the mario chips patent was a big help when i was hacking super fx assembler code in starfox 2. the patent even mentions the chips ability to access dram (instead of the standard sram) and something about a cd-rom controller iirc. not too sure about the last one, its kinda vague there.
Yes, I remember reading an interview with Jez San (?) where he said he showed a fast 3-D demo on the NES to Nintendo. (Was it accelerated or not?) Nintendo said it was nice, but would produce better fruit on the SNES/SFC.
Wasn't the same company who started prototype development for the NES chip the same one that was coming out with an NES cart that would 'upgrade' the NES into a full 16bit console? I remember reading an ad about it in an old, old, EGM (or some other mag) when I was at this locally owned video game store that was selling used game magazines. The ad was not about the Mario Chip, it was just a 16bit upgrade cart for the NES. Anyway, I'm still waiting for a TRUE SM64 sequel. To me SM64 brought mario into a whole new dimension, 3D (no pun intended there..). And it was done right. I loved the game. I beaten it, collected all the stars and just explored around exploiting the exploits. All Mario games since then have just been fillers, to give miyamoto more time to come up with a refined mario game that will certainly raise the bar once more.
During this time, Pete (Warnes) had been working on solid 3D on the NES, (no mean feat), it worked but it was clear that it would need some help in the CPU department so we started talking about doing a DSP type processor called the Mario Chip. Nintendo had just released the SNES and Jez had somehow persuaded them to use the "Mario Chip" for future SNES 3D games. NCL knew nothing about 3D but were very interested in doing a 3D game, so we offered to go to Kyoto to show them how to do it. So Dylan (Cuthbert), Krister (Wombell) and myself went to Kyoto and started working on what was to become Starfox. NCL did the artwork and we did the programming. source: http://cube.ign.com/articles/091/091276p1.html