I get asked this occasionally, so I will explain why I am reticent to do so.
The model is developed to be multi-part with all the mounting points in place, it was part of the process from getting from one big solid lump to the final design I don't have a mounting clean version.
So any single piece model would be a reassembly of the sub parts, and I would have to manually go through that process = work.
Anyone can take the STL's and do the same thing with a tool such as netfabb. This will be a good learning process for them.
Many people believe they have a compelling reason to need the one piece model, but few actually have the equipment to do something meaningful with it. Which would imply wasted work on my side. If they just want the overall solid, it is here.
If someone should have a compelling need, and the capability to do something with it, and yet not the capacity to do this work themselves, then they should PM me to explain why it is a good use of my own time. Not to say this is not possible, but I would take a little convincing...