I've always ran with Pioneer for it's durability. I have a Pioneer in my 83 L series that I bought back in 1995 and had it in 7 cars now, but it still plays AM/FM/CD perfectly. I've only owned 2 Alpines and they both broke in less then a year - tough luck for me I guess.
Alpine is probably one of the cleanest sounding decks on the market. Alpine has virtually no alternator whine, static, or any type of line noise in amplified systems and nonamplified systems.
Pioneer on the other hand, has good decks and bad decks. Definatly the longest lasting deck to be created. The new high end Pioneers have "clip in" RCA jacks on the back and those cause noise 90% of the time when you throw an amp into the configuration. If you want amped speakers with a Pioneer, you need to be ready to do some factory modifications like regrounding your battery, using larger guage wire to connect the alternator, and just other little stuff like that.
EDIT - They make a pocket to fill in the other hole that would be created by removing both the CD player and the tape deck. As for a video option...I haven't had the pleasure of putting any monitors in any stangs yet. Is this car a convertable? Does it have a sunroof? Would an overhead player be out of the question? Check on some of Pioneers Video/GPS units and check the length that it needs to stick out from the dash, you may be ok to just get an additional spacer.