I know for a fact that most of these stages I've had in my roster at least once. I just make SSP's for whatever stages I like. You can call me conceited for making my first SSP's of my own stages, but they're not my favorite.
As for the Stage Expansion mod, yes, I use it. I think everyone should look into using it. It's incredibly beneficial.
Of course your stages deserve sweet SSP's!
Of all time though, that Robz' stage has my favorite layout to fight on. Plus, I love urban environments
I'm definitely going to look into the stage expansion then.