My favorite jerk marinade was from the late and lamented Miss Pearl's Jam House in San Francisco. I never have gotten around to working up my own.
What I do these days is start with a store bought bottle, can't remember the brand name at the moment. Be careful with ones that list high fructose corn syrup as the first ingredient. Dice a couple green onions and some fresh ginger root to add to the store bought stuff, add in a pinch or two of ground allspice, maybe a healthy dash of cayenne or some chopped jalapeno. Great stuff to marinate wings or other chicken bits, various pork cuts and shrimp. Tried it on some salmon once, not that impressive - I prefer other methods of seasoning salmon.
Basically I suggest starting with a store bought base and experimenting with that to get a flavor you like.
Another thing I forgot - I often add a good sized splash of dark rum, like Meyer's, to the mix.
ps: There used to be a small place in downtown Palo Alto that had *killer* jerked wings, curried goat and such island treats. Another name that has fallen out of my memory!