Eighteen inch difference in wheelbase matters more for maneuverability than an eight inch difference in overall length. But it doesn't matter all that much, my 29-footer with 190-inch wheelbase also needs to make wide turns, has a huge turning circle, and I have to watch what the rear end is doing on really tight turns. Even my standard length E-350 van with 158-inch wheelbase needs to turn wide. The E-series does not have a particularly sharp steering cut.
If what you need in a C takes you past 30 feet of length, you should be looking at short (26-32 feet) A-gassers, which will give you more living space for a given length, better maneuverability (more steering cut on F-53 than E-450), and usually at least a ton more chassis capacity (might be two to four tons, depending on which F-53 GVWR the manufacturer chose to use). Unless you need the overhead bunk, you will find the same space in a A-gasser can be about four feet shorter than in a C.
My driveway RV parking area kept me under 30 feet, and in a C that is almost overloaded when empty, but if I could have used a 30-32 footer it would have been an A (Sightseer or Hurricane were our top choices in 2005) which at the time were actually less expensive than comparable size C motorhomes.
For similar trim level, fittings, floorplans and costs as the Sunseeker, look at Forest River's FR3 series. Nexus does not build shorter A gas motorhomes, but you might look at Winnebago's Vista/Sunstar, Jayco's Alante, Thor's Ace, all in the Sunseeker's entry market category.