do you have bucket seats or bench?
I too want some cup holders, I dont want to put the cup holder under the dash where a person seating in the middle might hit the cup holder with their knees.
What year is your truck? 60-63 with the curb windshiled has a perfect spot for cup holders, well at least I think it does, look at my int in the picture
also, look into boat cup holders, there are some nice ones out there and many swivel to keep the drink balance at all times