Now this is really something. Chris Covell of Your Weekly Famicom - a site set up to translate portions of old Weekly Famitsu issues - translated Capcom's commentary on the eight winning Rockman 4 boss designs. The original artwork of the winning submissions were published, too. I do believe some of these haven't been seen in 26 years!
Don't forget, this was the same boss contest that Yusuke Murata (Eyeshield 21, One-Punch Man) won. His winning submission, Dust Man, yielded the following comment:
"This one has a slightly unusual touch to its art. Naming the character 'dust', of all things, was brilliant."
*Chris' note: "dust" is Japanese English for "garbage", hence all the trash/scrap in the level. I assume the word was made via naïve backformation of "dustbin."
Check out all the winning designs and commentary here!