Consider maintenance in your equations as well. Sometimes up to 90% of the. overall cost of the truck is maintenance.
I think you need to look at your flow and volume. How many over the road trucks are you offloading a day and how much time are you putting away and picking? Can you justify two different trucks for these activities? Ideal would be to have one type of truck for each activity.If you can't then again think of what happens if your single truck breaks down? Talk to other owners of the model you are considering and ask them for their experiences. A very sophisticated truck with special components that have to be flown in from ? would be my nightmare.
I'm a fan of the Irish truck Aisle Master because it works in a narrow aisle and in outside yard conditions.It appears to be made from standard engines and components and looks like it is built like a brick shithouse. No I don't work for them or have anything to do with them.
Look around but first think form function flow and future. Any system you are thinking about will need some discipline in space dimensions etc that will somewhat lock you in. Will you be doing the same pallets and loads in 2/3/5 years? Can you easily add on to it.? Don't jam, it in to the racks to the last inch, add some inches to the beams to allow for overhang or for larger pallets.
I can help if you E mail.
Thanks