my thought : have you ever played with fibreglass before?
a few bucks of resin, and some CSM, with a few hours, and presto. your own tonnea cover. probally look better too.
Id estimate about $200+ to make though, by the time you bought all the crap you would need for a first timer. so yeah. just visit repco, or call up the wreckers. might just pick yourself up a bargain