This wasn't some passing notion -- there's a reason the two characters look almost identical aside from the hair and makeup. It was supposed to be an elaborate joke about Bart and Homer's relationship. Bart thought his boring old dad was lame, when in reality he was a misanthropic were-clown that entertained children all across town.
20th Century Fox Television
Whoa, we're seeing double here! Four father figures!
The idea was eventually dropped for being too complicated. It would have stretched believability a tad to show Homer successfully leading a double life as a local celebrity while maintaining a job at a nuclear power plant and also barely being competent and sober enough to tie his own shoes. Not to mention all those early storylines about the family's financial troubles would have lost a bit of punch if Homer was secretly sitting on a wealth of branded Krusty home pregnancy test and imitation gruel royalties.