Jetti.co (now getnomad.com) is another company that rents the SMB converted Metris Mercedes Vans. They are in SF (Treasure Island). When I visited the Fresno facility this Summer 2017, they had 20 pop top Metris orders to deliver.
The XL Flex features an adjustable height rear bed that provides flexible gear storage/sleeping configurations. Looks perfect for interior bike storage.
I've seen SMB builds with open gear storage below the platform bed, but I don't think SMB offers the adjustable height option.