To my knowledge there no rv or expedition trucks out there with seating for 8. You are looking into bus size! Aside from the secure and certified belted seating, where do you set up 8 beds and still have room for a bathroom, kitchen and room to store all your gear? Not even talking about sporting gear like bikes etc...
I would seriously consider two vehicles. These can be much smaller and will get you to much more places. In that case your $150,000 may be a bit tight.
Good luck!
I know this is an old thread, but the two units he is looking for are a really unique layout for families.
8 seatbelts (4 in quad cab + four around dinette)
Sleeping for 5 adults or up to 8 if some are kids (queen bed, double dinette, double couch, single drops from ceiling).
All in an F550 with four wheel drive.
It’s basically unheard of anywhere else.