Hi,
I had searched the forums for ideas for carrying my two 60 pound Standard Poodles in the back of the X5. There are barriers and liners but, to me, both mean that the dogs will still destroy the trunk area as soon as they see their first squirrel.
So I was delighted to find these soft crates at a local pet supply store (internal, collapsible steel frame... ventilated all sides with both a side and front door).
FIRSTRAX
30" deep by 21" wide by 23" tall.
As shown below, two of them fit perfectly side-by-side with an inch or so all round for clearance. They are very well made and still look new after daily use over many months.
I also bought two of the white interior mats (sold separately) and popped one out to show the rubberized floor of the crate.
Note also, I have a factory rubber liner (look closely) for general cargo use as well as a strip of rubber "runner" from Home Depot to protect the tailgate from claws and other cargo bumps. It just folds up and out of the way.
The dogs jump right in and are perfectly happy, even on longer trips, and often just curl up for a nap in their secure environment. Even though the "recommendation" is for "up to 40 pounds" the crates are spacious and comfortable for mine.
If you only need one, the side door makes lengthwise placement a snap, even for a larger version of the crate.
Maybe this helps you. Cheers.
Ian