ive always thought a fire/dragon type with levitate would be awesome. it still has a few weaknesses. and grass/dragon would be interesting too - keeping the dragon's curse (4 x ice weekness).
i think levitate would be good for
etc, although there are probably hundreds who should have levitate if we just go by logic. eg
and some of the butterflies....
and i guess it probably wouldnt be such a good idea to just change everything to dragons. they are pretty cool, but its often the case that dragons have high attack and lower special attack, making it hard to utilise STAB on dragon type moves......