Hey has this been pointed out? Potentially interesting, so heres texture rips.
https://mega.co.nz/#!I8tAQTxA!nPwyw_7tWJi96dzzCeOlsK_fTYdTLgXzPLRe4tqWsf0
Extract and search for chr_10_page you'll find these.
Their file names are "chr_10_page_1.tex (AFE29875-55.bin)_0" and "chr_10_page_2.tex (AFE29875-56.bin)_0" They are grouped and the same size as character select icons.
Checked out stages and the same thing exists too.
stage_10_page_1.tex (0DFEFCCA-39.bin)_0 & stage_10_page_2.tex (0DFEFCCA-40.bin)_0
Looks like something that could be used for DLC, doesn't confirm anything for sure as they could be left overs from when the CSS or such was bigger but yeah think this would fit so well with that current gap in the stage select screen.