might also might want to try an Onyx Reserve.
Took the words right outta my mouth (or off my typing fingers?) -- the Onyx mads are just the slightest bit sweet, but it's a natural sweet, and have this "side of the tongue" salty/ bitter component (not acrid, just ... ? can't think of the word) that seems to bring it all together.
I think someone said it already, but the 5 Vegas serie A line has a strong mocha/ coffee- chocolate, as do a bunch of other lines with Costa Rican tobacco (Bucannero comes to mind, as does Felipe gregorio's "Pelo de Oro" and "Power" blends)
Not sure if this is too far in left field to be considered "on topic", but I've found a that a black- licorice flavor often accompanies chocolate flavors. If this is for you, I'd hands down recommend the (Dominican) Cohiba XV (Extra Virtuoso) or the St Luis Rey Serie G mad (which is
totally different from their normal line.) Both of those have a 50/50% chocolate/ licorice blend, at least to this underdeveloped palate...
Hope this crazy- long post helps a tad. Just my 2 cents,
ZugbugPete