The rule changes mean it's hard to find a bat certified for both major associations, but DeMarini solved this conundrum with The One, a new bat for this season. It may not break-in as fast as the single-association bats, according to company reps, but it should perform well enough to keep your team competitive until it reaches its full potential after a couple hundred hits.
If you're looking for something a bit more affordable that you can use in absolutely any non-wooden bat competition, you'll have to go find a single-wall metal bat, which is basically a well-formed metal tube. Anderson is the bat company that innovates in this category, but this isn't really where you should be looking for innovation. The DeMarini Ultimate Weapon gets the job done. [$99 and $299; demarini.com]