A viv like that would be more suited for arboreal lizards than snakes. Having such a great height means regulating the climate in the viv will be a bit more difficult, something that most arboreal snakes will need spot on...
Having a lower viv with a decent width so the snakes can move along branches tends to work well. Most chondro breeders for example use 2ft - 3ft tall vivs
As for a good 'starter' species, Amazon Tree Boas seem to be very in at the moment and for good reason too... They're incredibly polymorphic with all sorts of colour phases and patterns popping up in litters, fairly hardy compared to Chondros and Emeralds, and they're also being bred in captivity on a regular basis now, meaning that finding good healthy reasonably priced CB young should not be too hard 8)