Yes I have a set of 6.5 components in the doors, mdf round spacers required and you need to shave a little off of the inner side of the door card, well worth the little extra effort involved though.
I followed a guide on here somewhere, a number of members have done this.
With 6.5 there is a much greater speaker choice both in quality and price than you get with 5x7s.
Crossovers fit behind the door cards without any problems too and the tweeters can also easily be replaced.
With a component set of 6.5s you should get two 6.5 woofers, 2 tweeters and two crossovers.