I've never used a Jaguar, so I can't really comment on it (well, I did try to emulate a few of it's games, but the emulator was less than perfect, I keep meaning to try it now, since so long has passed the emulators are probably a lot more accurate now), but when I read about the console being twenty years old this year I looked through the Jaguar forums at Atari Age for information, and the Jaguar does have some very loyal fans. I don't know how many, so I don't know if it would be cost effective for Krikzz or anyone to develop a real backup cartridge (as opposed to a Skunk board, which if I've got it right doesn't allow for game saving, only holds two games, and has to be connected directly to the PC to transfer game roms across), but the Jaguar must have something good about it to have such loyalty, even if from only a few users.
And the Jaguar does have a much more active homebrew scene than the N64, although I don't know if Jaguar game hacking/modding is as popular as N64 game hacking/modding (well, game hacking on the N64 isn't exactly common, but thankfully the games that are altered are mostly very good, such as Perfect Dark, Goldeneye, Super Mario 64, Legend of Zelda: Ocarina of Time, F-Zero X, etc). And the Jaguar homebrew scene does seem to be still fairly alive, as opposed to the (much easer to program, with a much larger user base) original XBox, which once had a *massive* homebrew scene yet nowadays the homebrew is almost dead.*
There are even dedicated events such as Jagfest, where Jaguar fans meet up to discuss/play and swap software/hardware for the Jaguar, but I don't know of anything even remotely similar for either the N64 or XBox, despite them both having far more users and games.
* Well, XBox homebrew is now very rarely released, but of course the huge number of past hmebrew releases are still available, and many of them are still well worth using, such as ports of games that had their source codes released (Doom 1 and 2, Quake 1 to 3, Duke Nukem 3D, Alien vs. Predator, Shadow Warrior, Descent 1 and 2, Cave Story, etc), a *superb* media player (XBMC, that plays just about any movie or audio format you can name, it's only failing is that (due to the XBox's limitations) it can't play hi-def movies or Blu-ray discs), fantastic emulators for just about every 8 and 16 bit console/computer you can name, and even emulators for 32 and 64 bit systems (such as the Playstation and N64, though here the performance and compatibility is often much less satisfactory, depending on the game you're emulating, again due to the XBox's hardware limitations).