You probably wont find a board that is going to handle great for park and boardercross. You'll need two boards.
If you want to compromise both, the Turbo. Its a great all mountain board, will be OK in boardercross, and pretty good every in the park except some techy jib stuff.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping