Tambox,
I reckon that is a rare and unusual truck- there is probably a bazillion people who would like it. (not so sure if there is a bazillion people who would pay for it?)
Put some photos up if you can, I'm sure someone will inbox you. I'd love to have a look at it just for interests sake.
I really think it's almost impossible to value things without clarity on what it is, it sounds like it would be a terrific truck, but what can you compare it to, for a valuation? And everyone certainly has a very different idea of what is good / bad /cheap/dear and so on..
And I honestly think that you could almost name your price- if you want to wait. If you want to sell it in a hurry, then you need to get the price down to where the phone starts ringing.
As an example that MAY assist, on Bookface there is what appears to be a very tidy, genuine and original Flintstone Mack, with a tipping tray on it, in NSW- They are asking for ideas of value, with a figure of $30K as a guide. no one has bought it yet, but surely it should be worth around there somewhere. For a quicker sale, if they got the price down to low $20's, the truck should fly out the door (says me, anyway). Under $20K would be a gift, but that is or course, if you want a Flintstone Mack!
Not sure if this helps you or not, but I am certain we would all love to see your truck, and someone just may make you an offer if you put it on the for sale section.
Good luck with it and don't hesitate to ask questions- I've found this forum to be a great source of information.
Cheers
Rich