If you're going all black, you may definitely want to consider the Angelus paints, they've got actual leather paints made specifically for leather, and moving parts [not like some of the other stuff with is craft paint (not made to flex)], they've also got dyes, waxes, and cleaning cremes and compounds.
I carry lots of there stuff... if i don't have it i will within a week.
They've got this great cleaner for leather, and trust me, if it'll make a raggedy ass pair of my wife's Reebok's sparkle, it'll do a interior which MOST times see a lot less action then a pair of kicks.
they've also got a deglazer/prep that will deglaze (take protective coating) of leather, so the paint will bond, and also have finishes for the leather paint, in case you want a bright gloss, or perhaps a matte finish.
Find out how much that SEM costs for me and let me know, and i'll see if i can't beat it with my guys stuff.