The color I'm "saving" for my Fretless M5, for lack of a better description, is a "Denim Blue" that truly does look like a pair of jeans. I saw it on a bass
years ago for sale on Adrian Garcia's website (at a price that sold so low it still sickens me to this day

), fell for it immediately, saved it and have kept it "tucked away" ever since. I have somewhat of a tradition of my fretless basses: my first "starter fretless" was a 1992 Ibanez SR-800 in "Pearl Blue", my upgrade/"got schooled on" & DIY defretted it myself and installed matching blue fretlines using Blue Purfling for an Acoustic Guitar... which came out
killer, and currently my Spector Euro Bolt-On with custom Nordstrand Big Singles, Aguilar OBP-3 & HG Thor Epoxy Fingerboard Coating beauty of a fretless bass being "Blueburst", so this would continue that while bringing "a new blue" to the table - "Denim Blue" with an Ebony 'board and matching headstock
(not sure about Chrome or Black hardware, however. Chrome looks great in the picture, but Black, besides being "me" would match up nicely with an Ebony fingerboard) 
)...