Hi Simon,
There is another option to take on your trip, and one that packs not only aperture, but also packing piece of mind.
I recently took my two 12" Marana reflectors up to Queensland's Astrofest this last weekend. In the car was also my 17.5" Karee dob. All packed into the one car along with all my camping gear and stuff. The two 12" scopes packed one on top of the other. Have a look at the pics below to see how jammed in everything was into my Mitsubishi Outlander. A round trip of 2150km from Sydney, and each of the scopes is in brilliant nick, safe and sound. I've already clocked up several thousand kms with the two Marana, and many more thousands with the 17.5".
What you don't need on a long road trip is to have to walk on eggshells because you have a scope in the back. I designed my Gondwana telescopes with this very thing in mind, and give an aperture that packs some considerable punch. Kinda leaves your current 8" dob shaking in its boots, eh!
How does Marana perform? Well, it's had a 13mm Ethos with a Paracorr hanging off its focuser, and the image stayed tack sharp!
Oh, and the scope is perfectly balanced too - no action changing mechanism in sight.