I loaded about 110 sq ft of bathroom tile in. No suspension problems either.
Another time I fit my 80lb Greyhound (dog) in the back, with the seats folded of course.
For this the MINI is MUCH better than a pickup truck. Only white-trash carry dogs in the beds of pickem-up trucks.

 

When my pick up truck (74 Explorer) and I HAD to get the dogs to the kennel for boarding over the holidays ...I managed to squeeze in:

1. - Annie-26 lb Cocker Spaniel
2. -Maeve-97 lb Shepard Mix
3. -Stu-62 lb. Staff/Lab Mix
4. Me

It was a short trip and I don't look forward to it again but they sure like that little car!

 

Sounds like your bathroom is just about big enough to park your MINI in!

 

I plan on fitting my 130lb great dane and my chocolate lab. Shouldn´t be a problem. The big dog fitted in my old bettle´s back seat!

 

I built a removable platform to fill the boot compartment well to make one large flat area when the seats are down. I attach a 2.5' wide X 6' long folding ramp to the bumper which I use to drive a three wheeled electric scooter up the ramp and into the hatchback area. The ramp is refolded and stored with the scooter. I need the scooter to get around faster at the A.C. casinos.

For what its worth

Keep Motorin'

Dan