I am going on a long 200 mile tour over 3 days with six other people. We are riding down to Washington DC and then renting a car to drive back. We thought we could rent a Van or SUV and have two people drive that and fit all the bikes in it if the seats fold down. Then Rent another car for the rest of the people to fit in and drive back.
The bikes will mostly be 26 inch tire bikes with medium to large frames. Two of the bikes will be large framed 700cc tired bikes.
I fit 5 beefy mtb bikes in the back of my small Nissan frontier without taking anything off. 7 can be done but you will have to remove the pedals, it is the only way. Also, alternate the directions the bikes face. Removing the seats will help as the handlebars will want to hit them.
They will get scratched to heck, no matter how hard you try otherwise. Watch that nothing is near the stanctions. Your shifters will want to rub on the adjacent bikes frame. I wouldn't do it with new bikes ... but if they are already scratched, what's an extra rub mark?
You might also want to see if the van has a trailer hitch. You could either pull a small trailer (u-haul or other rental places will rent them) or use a bicycle hitch mount.
With this option, be sure to lock the bikes solidly to the hitch mount or trailer with the sturdiest chain lock (not cable lock) that you can afford. It's very easy for someone to snip a cable lock while you're waiting at a red light or at a fast food drive-thru and steal your bikes without you even noticing.
Look for a company that will rent you a real van. You can get like 10 bikes and gear in a Chevy Express or GMC Savana with the seats removed. I can get easily get 4 or five bikes in the back of my Savana and still have room for other stuff.