I answered a PM from Eric about this but I'll mention a little about it here. My toter is on the same truck that he is looking at. Mine has a 12' living quarters on it and is quite heavy on the front axle. The added weight flexes the springs and I think that the ride is pretty good. The rear axle is Freightliner air ride. Overall the toter is 30' long and the wheelbase is almost 300" The turning radius on this truck stinks! I can put Dad's Prevost in places that this truck will not think about. The front wheels do not turn very tight at all compared to many other trucks that I have seen. I've been told that this is typical of the FLD. Eric, if you are planning to stretch the chassis keep the turning radius in mind.
P.S. Eric mentioned reducing tire air pressure. The guys on one of the bus conversions forums have been doing this with very good results. Tire manufacturers have different air pressure recommendations based on the load that the tire is carrying. Eric could scale each axle of his truck and adjust the tire pressure for the weight that the tire is carrying. I'm planning to do this with my toterhome.
1989 FLD120 with 2000 NRC conversion