Not for cars, but you can get pretty close. For a speaker system to compete with the noises in an EB, it has to move a LOT of air. That means you either need a lot of cone surface area, or you need expensive long throw coils with a lot of amp to drive 'em.
I've seen tests in stereo magazines that show for real world listening in a car, you shouldn't go with more than a 2:3 ratio when getting oval speakers to avoid distortion damage. A 6x9 would be ok, but a 5x10 would be pushing the limits. So, a good sounding car speaker quickly gets too wide to fit under the dash.
A good compromise that I'm running is seperates. A decent sized mid/bass hidden any where you can fit it, combined with some small 1-1/2" tweeters under the dash facing the passengers. The mid/bass fills the Bronco with sound and the tweeters give you the detail and stereo separation. Sounds great and they're out of the way. The only drawback was also having to hide the passive crossovers. The crossovers should have been very small and cheap, but Kenwood put them in a large plastic box. ...I guess some guys like their stereos to LOOK big.
