A couple of the very high end RV parks we have stayed at offer the very sites being discussed here. Two that come to mind, Osprey in Alabama & Blue Heron on the banks of the Klamath River in California, allow only Class A's in these premium sites. I found it ironic that at both of these beautiful parks, people with towables complained that they now had to contend with what we motorhome types accept as normal - parking with our 'backs' to the view. We visited a beautiful park on the bay in the Gulf Shores area that offered hook-ups located so that either type of RV can enjoy the view from inside. This results in the dreaded side-by-side situation wherein your neighbor's door & yours open to each other. No thanks! Providing sites that allow motorhomes to face the view, without the dreaded side-by-side, may result in a few disgruntled towables driving on, but I have no doubt that this would be more than made up for by those of us with motorhomes.
You'll note that when you open this very site under the 'Plan a Trip' heading, that the very first 10/10/10 site identified is the aforementioned Lake Osprey RV Resort. Distant Drums is also a 10/10/10 park. Sounds like a park offering pull in sites to motorhomes only would be part of a pretty special group!