i'm supprised more people didn't jump on this..
ok.. why don't u want to use a truss rod?
it can be done, virgier uses a laminated maple/carbon/maple neck. But that's prettypricey. If u can get ur hands on some ebony and laminate that thru the whole neck thru it should be ok depending on how wide a stripe u use, but ebony is EXTREMELY expensive, bubinga, padouk, Palisander Rosewood, purple heart, bloodwood, wenge, and zircote are all excellent hard woods that are at least half as expensive as ebony to make the neck thru out of if u don't want to have a truss rod, however, they are going to weigh a bit more, and i would recomend having a 3 or more peice laminante neck. I read up on these woods here
http://www.warmoth.com/Guitar/Necks/neckwoods.htm
ur best (and cheapest) bet would probably be bubinga, purple heart, and bloodwood and i'd use 5 half inch wide boards and lamitate it together.... so get 2 purple heart peices, 2 peices of bloodwood and one peice of bubinga all 1/2"x2"x 40" and glue them together. Out of that peice of laminated wood u can get ur neck thru and at least 2 fingerboard blanks if u cut it right.
If u need me to explain that a bit more clearly just ask.
Derek.