"Yes, I was trying to find that info as well. I assume that a FDS ROM can be put on a NES cart as long as the ROM doesn't use any enhancements that the FDS of FC has over the NES."
One would think, but it makes me wonder why the NES emulators that support FDS
games need the BIOS from the FDS to even be able to load the game.
I hope what you said end up being correct though, because I would eventually like
the original Super Mario Bros. disk system version to be on a cart, because the
minus level trick acts very differently from the cart in that version. I have
personally tried it out on this version, and it is certainty interesting.
In the Famicom Disk System of Super Mario Bros., the Minus World is accessed the same way, but is very different in design. World -1 is just like World 1-3, but with underwater gameplay (despite lacking actual visual water) and featuring bizarre elements such as multiple floating Princess Toadstools and a floating Bowser, as well as an overall glitchy palette for several objects.
Source:
http://www.mariowiki.com/Minus_World