I say go for it. Ipe is one of the few woods I would use in a truck bed. Common hard woods like Oak, Maple or Beech are only about 1/3 the hardness of Ipe, which is the 13th hardest wood in the world and the 16th heaviest. It will sink in water. The main reason to use it is it's durability to weathering and its rot resistance. You will not have to use any sort of finish on it if you park indoors it will look the same for decades. If you park outdoors it will turn a nice dark grey color (my preferred look for a truck bed) that can be renewed with a pressure wash a quick coat of a Tung Oil type of finish.
The other woods to look at with similar durability (but not as hard or heavy) are Osage Orange and Black Locust. Osage starts out yellow and turns to a medium brown with exposure to UV rays. Black Locust starts out a light brown and darkens with age also.
If the car manufacturers had used these timbers as original equipment, our friends at Mar-K would be only sell sheet metal.
Don't forget to post pictures when your done.
