The way I have always done true piano black finishes, is by first putting down a coat of flat black paint and then doing multiple coats of lacqure. Its an extremely time consuming process to get it to look good. I dont know if this is what you had in mind when you mention gloss.
I used a satin black on my subs and I think it came out great. I used some american accents (by rustoleum) paint from lowes and sprayed it on with an HVLP sprayer. I used two coats of primer and a couple coats of black. I was pretty impressed with how well the paint adhered and it was easy to work with.