First the bad news: Apparently all the Ceroxylon in cultivation grow very slow (think Jubaea) I guess that means that those 200ft. monsters in Columbia are either very old, or they grow much faster in the wild; I guess however that in zone 8 a trunkess feather palm wouldn't be such an awful thing :). Ceroxylon seed of various species have been distributed in California for over twenty-five years, and there is little to show for it.  There are only a few trunked ones in cultivation, and many older ones are just beginning to show trunk after 20+ years.  Many in Southern Cal. perish understandably from too much heat, and the dry Santa Ana winds- or a general lack of humidity.  Some people in California find that they are successful using an overhead misting system to keep these palms alive.  In the S.F. Bay area Ceroxylon is easier as a result of the cool coastal climate which stimulates the cool, misty high altitude forests of central america where temps rarely vary more than a few degrees from the yearly mean.  The good news: I do have a reference which discusses cold-hardiness and I will try to post info, it is fairly promising for some species, but again low temps may not be as troublesome as the difficult cultural requirements of this genus.

eddykrif

First a correction to my previous post; I meant to say South America, and not Central America when decribing the native range of Ceroxylon.  The only hardiness data I could find was that in northern California C. alpinum began to show frond burn in the mid-twenties.  C. quindiense was conpletely undamaged at similar temps, but is less heat tolerant than above.  Ceroxylon can be found at Strybing Arboretum in San Fran, across the bay at Oakland Palmetum, and at the Huntington Arboretum in Southern CA.  This same article listed C. parvifrons (utile) as the best Ceroxylon for the bay area, and (as yo umay suspect) the most cold-tolerant.  Ceroxylon hexandrum was also mentioned as hardy in the S.F. Bay area.
One more note about growth rate: apparently like Jubaea and Juania australis, Ceroxylon grows extremely slow until it begins forming a trunk at which time it "takes off" and grows relatively rapidly thereafter (which may explain the height question) nevertheless the time it takes to begin trunking maybe as much as 30+ years from seed for some species.  Ouch.

Eddykrif