First of all, redtailed greens are simply aggressive...lol Seeing as there are so few of us working to get captive bred stock, and with a lot of the problems we've encountered, I personally haven't seen an CB adults, so their temperments could be much differnt. These truly are, beautiful snakes, but they are very hard to keep, especially as WC specimens. I've been fortunate and have been able to successfully aclimate 3 out of 4, but I've heard of entire shipments falling out...very prone to parasite problems from the wild.
I've found the beauty snakes to very impressive snakes, especially when it comes to a display animal. One not mentioned yet, that would prbably fall into perfect suit for what you are looking for is a Kunisar Island Rat. Especially if you can find good specimens with lots of turquoise green/blue color.
Or another good display snake that could work for you, if you like the black/yellow offset, are tiger ratsnakes. Again, a very mobile snake, awesome threat displays, arboreal, reaches up to around 8ft, and very cool!
Just my two cents though...below is last year pic of my Kunisar female with her clutch...

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Conrad
Too Fast Reptiles
www.toofastreptiles.bravehost.com