When the current superhero movie boom was in its infancy, we could have been teased with the crossover to end all crossovers. Hugh Jackman says he almost did a brief cameo in the first Spider-Man movie as Wolverine — but it fell through because he didn't have the right costume.
Top image: Gemelli22 on Deviant Art.
Talking to the Huffington Post, Jackman explains:
In the first "Spider-Man" — Kevin Feige reminded me of this — we really tried to get me to come on and do something, whether it was a gag or just to walk through the shot or something. The problem was, we couldn't find the suit. The suit was stuck in some thing. And so when they were in New York when I was there, we couldn't get it together.
He goes on to say that he'd still like to do a crossover now, if the studios could agree to split the proceeds and put him in a movie with Robert Downey Jr.'s Iron Man — but there's just too much money invested for the studios to want to do that. (Which is the same reason why Logan's cameo in the first Spidey movie, if it had happened, probably wouldn't have led to anything more substantial.)