Band-Width <> Bandwidth
The term "bandwidth" referrs to frequency spread and/or information throughput capacity. It sounds like what you're trying to achieve is a "wall of sound"* type of effect where a sound from one source appears to be eminating from a wide area instead of a point location. While that may possbily be humorously slanged as "band width" (the physical width of the band's sound in the stereo sound field), it really has nothing to do with the technical term "bandwidth."
Interesting theory you have there, but there are a lot of questions/potential problems involved. First is, of you're talking about doing this with one instrument/original track, you're not leaving much room in the soundscape for everything else. Second is, if you're talking about mixing the whole mix down to a mono track and then applying all these delays and pans, you could still going to wind up with a centered mono sound that won't necessarily sound all that wide because of the Haas effect.
I'm with Benny, your bpm numbers mean nothing to me when talking about delay times. Without knowing your actual delay times, I can't say just what will actually happen, but if the delays are fairly "typical", you'll come across the Haas effect, sometimes known as the proximity effect. This is a psychoacoustic effect where then there are two panned signals with a slight delay between them, the first signal will be perceived as being louder than it actually is,
regardless of the volume of the second signal. In theory this effect, when applied to your hypothetical setup, would tend to reinforce the perceived volume of the centered track(s), thus pushing the perceived emphasis back to the middle and reinforcing the centered mono sound.
Now perhaps this might be a trick that can be used to boost the perceived volume in the center without using up headroom and bypassing the RMS problem that everybody seems to be so concerned about this week, but the cost in stereo soundspace usage is extremely high.
But, Abomination, I'm just theorizing here as well. I have not tried it any more than you have. Again, I'm with Benny when he asks "Have you tried it?" It's not like it would be that hard to try, why not just try it and see what happens? That will be worth more than a million specualtive posts from us boneheads.
G.
*Not to be confued with the Phil Spector "Wall Of Sound" effect, which is completly different and was usually actullay done in mono.