Is it possible that Foreman Spike was once supposed to be the character of Waluigi?
To start with back in 1985, Foreman Spike made his original debut in Wrecking Crew for the NES. He was what most would interpret as the main villain of the title, as there was no sign of either Bowser of Donkey Kong within the title. His appearance was somewhat similar to that of Mario, except he had a bushy beard and what appears to be a hooked nose.
Moving forward to the development of Super Mario Land 2, Nintendo obviously wanted to bring a new villain to the title, specifically an evil brother. Looking back at the catalogue of previously created characters, from a far away view, Foreman Spike would be able to fit this build pretty well, considering the character design was already strikingly similar to that of Mario and Luigi. But the development team expressed distaste to the idea of relying on prior character creations within the original Super Mario Land and wanted to make their own, hence Spike was left on the cutting floor and Wario was born.
Years pass until the revival of the Wrecking Crew franchise with the release of Wrecking Crew 98 for SNES in Japan. This title sees the return of Foreman Spike with a redesigned look, with a much thinner moustache, no beard at all, and a slimmer build. Oddly enough he almost looks like a character that would come out of the WarioWare franchise.
During this time Camelot was also developing a number of titles, which included Mario Tennis for Nintendo 64. Prior to this title Camelot had a history for including original, new, characters within their Nintendo themed games, such as Plum, Charlie, and Harry in Mario Golf for N64 and GBC.
It's likely that initial development of Mario Tennis originally had this idea as well, to include original Camelot characters aside Mario characters from the beginning. For whatever reason this was changed, probably due to the large back catalog of Mario characters, it made no sense to resort to making new no-namers. And thus Mario Tennis became the first Mario spinoff title to really include characters within the series that had been missing for years. If you think about it, Mario Golf and Mario Kart traditionally had very staple, mainstay franchise characters (with the exception of maybe Baby Mario).
Camelot needed to fill the roster lineup, and clearly wanted to include characters who would be very foreign to gamers, yet a pleasant surprise to those who remembered. Hence the inclusion of characters like Birdo, and Princess Daisy. Yet the one odd character out, was the creation of Waluigi, who made his debut in Mario Tennis for N64. What likely happened is that Camelot wanted to use Foreman Spike in Mario Tennis using his revamped design from Wrecking Crew 98, but due to his extreme obscurity of not seeing a Western appearance since 1985, Nintendo said to cut him out or retool the character (as it was probably seen his lanky, swift moving character was unmatched by other players and should stay in). Thus Waluigi was created, yet retaining many of the qualities of the new Foreman Spike design.
Further proof of this is the fact that during or after this development of Mario Tennis wrapped up, Camelot was also designing Mobile Golf for Game Boy Color. A fairly obscure, Japan only title, that was developed to be compatible with the mobile adapter which would allow for online play through cellular data.
The title featured a mostly Camelot specific cast, with a few appearances of Mario characters such as Mario, Peach, Yoshi.... and Foreman Spike. Not only is he a completely random character to include, but Camelot also changed the design of the character to match the colors of Waluigi.
Furthermore there is other connections to Waluigi and his Foreman Spike background in other Mario titles such as,
- Waluigi drives a crane in Mario Kart DS.
- Waluigi's special in Mario Superstar Baseball is the Whiskered Eggplant. The Eggplant man was the other main villain within the Wrecking Crew series
- Waluigi's Island in Mario Party 3 is heavily influenced on industrial design (such as construction work).
- In Dance Dance Revolution Mario Mix, the song that represents Waluigi is the Destruction Dance, which is a remix of a Wrecking Crew title.
Sorry for the long post, and maybe most of this is known, but I did not know a lot about the details behind it.