Back in July of 2004, I was at the pinnacle of my gaming age and the Gamecube was king. I had bought some gaming magazines form time to time. Today I dug up an old Tips & Tricks magazine from July 2004. The now defunct magazine often published many cheat codes, game previews, and walkthroughs. This bit caught my attention though and I have a scan below.
The Nintendo DS had just been announced around the time and that explains the hideous prototype. In the list of possible games, Mega Man Battle Network is listed, but no other exact title is given. But of course there are other temporary titles like "Super Mario 64 x4". But here is what strikes me as odd. In July 2004, MegaMan Battle Network 4 was recently released in the states and BN5 was due for release in Japan on winter of that year. So if in July 2004 they anticipated a Battle Network game, I have a feeling it wasn't going to be a port of MMBN5. Look at the other games. They had so much more development time and budget going for them. In July 2004, I think BN5 had just been announced in Japan. And I think the Team Colonel version wasn't even considered at that point yet!
My guess based on this is that a different Battle Network project was in the works around this time, and for whatever reason, never saw the light of day and it turned into a BN5 port. Looking back at the unused 3D models from Star Force and the unused animations from BN5DS, it could mean a 3D version of BN5 was being worked on simultaneously (which sounds crazy) or something else entirely. Either way, for a launch list of Nintendo DS games, BN5DS delivered the weakest punch, which is a shame considering it could always have been much better. They wanted to do something more daring, but now that the NDS is on its way out and all we got was 2 mediocre Battle Network games on it, it's a shame Battle Network never got a game with a higher budget, longer development time, and less recycled content.