The E450 4wd conversion is almost $13k from Quigley and I didn't see anything on the Phoenix Cruiser site about 10K lb towing upgrades. The limitation is usually the rear RV extension off the vehicle frame. The more custom I request, the more the price will climb and I would not be surprised if it will be above $150k when done.
The Super C's are competing against truck camper setups for my next upgrade. For those of you less familiar with current truck campers, realize that they can have gensets, solar, satellite and slide options just like a MH or TT - Some even have washer and fireplace options. To give you an idea of what is available in truck campers:
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A fully optioned Class 4 or 5 truck and one of the above fully optioned truck campers will be under $150K. If you scale back some of those options, the price is closer $125k.
This is our current floor plan with dual group 29 batteries, 42 gallons fresh water and 60#'s of LPG:
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This setup would be about $75k on a new SRW Class 2 or 3 truck.