Well, rollerskates... hm, it's a nice twist.
However, I would like to see various forms of transportation myself, or maybe improved advances on your transportation. For instance, in Pokemon XD, you get to ride on your scooter, but, over time, your scooter gets upgraded to a scooter that hovers! And later on, you get a transportation built for you -- the RoboKyogre. So yes, basically, if we get rollerskates, I'd like to see maybe either upgraded versions of that, or, maybe just different types of rollerskates, like one type that allows you to jump like the Acro Bike, or hey, maybe one that sort of 'hovers'? Or.. .you know, maybe just plain ol' Ice skates?
Hm, I'd like a skateboard too. Or a scooter, because, scooters are also fun, and they're a nice refresher on getting around everywhere.