I guess I'm biased, but......
- It sounds like you need a scope design that many of the top planetary imagers here use (albeit BIG ones)
- A scope that can be easily modified to give a relatively flat coma free field (with corrector)
- A scope with big enough aperture to allow observing and imaging of DSOs without oversized central obstruction
- A scope that isn't too heavy for a HEQ5Pro
- A scope that's great value for money
I'm just saying why leave out the humble 8" Newt from the equation? I don't have any experience with 10" ers - probably going to need EQ6 with an additional ED80 hanging off the side.
Portability, size for transport and ease of transport I suspect are key requirements as well as optical performance from the scopes you have described.
Might be worth looking over some of the work Eric Lo has done with reflectors (Ezystyles on IIS).
http://www.ezystyles.com.au/