What is the most aperature I can carry?

I have a 10" Dob that is a lot of fun, but is too long to easily move in my car. I can pick up the entire thing while it is on its base (58 lbs), but not much more than that. What I want is the most aperature I can possibly lift and transport (by car), on a tripod/mount that can hang with a planet at 300-400X long enough for other people to get a look. With the Dob I have to put the object out of the field of view, let one person look as it moves through, reacquire the planet, and repeat. I read somewhere that Celestron SCT's weigh less than Meade's - but are there other options (Mak-Cass, other brands of SCT, other types of scopes)? Goto is not necessary, but the mount would have to be strong enough to take a 6lb piggyback - a 4" short-tube achromat. Budget is not so much a concern as value - I would rather pay $3,000 for a wonderful used OTA/mount that will hold its resale value than $2,000 for a tricked-up brand new GPS mount that will be worth half once the next line of electronics rolls out.

Thanks -

Ryan O

A while back Sky and Telescope had a piece about a guy who mounted his scope on a car trailer. That way you can keep your large aperture and have portability as well. It might need to be recollimated each time, but that probably wouldn't take much longer than setting up an SCT on an equatorial mount.