When way too much is not enough...

[pipopak]

get one of these:
http://www.roadtransport.com/blogs/big-lorry-blog/2011/11/04/Powerhouse_Coach_-_luxury_motor_coach_based_on_Volvo_NH12.jpg

[RoyJ]

Good luck parking that thing!

I find a common design problem with truck conversions is axle weight distribution - way too much on the steer. Look at a typical factory built Class C, the rear axle is almost half way up the chassis. And it should, because all the weight is up front, unlike a coach.

Then you look at a truck conversion, the tandems are too far back. A lot of them put 18k on the steer, and only 25k on a rear 40k+ tandem 

[Jeremy]

Impressive, but I reckon this one's bigger; twin full-length slides in a F1 motorhome:

[kyle4501]

It is surprising how many professional & factory built motorhomes are built with no regard to actual loaded weight when used as advertised. 

Just because the body is uniform, that does not mean the mass is evenly distributed. Far too many place too much emphasis on cosmetics & not the underlying mechanicals . . . But paint & polish seems to be what sells . . . 

However, any good coach (or truck) builder will pay attention to axle loading & place the paint & polish accordingly.