Haven't heard of them, we made the servers work in our normal racks however it's a little bit of a task to do as they don't fit into the racks without being put in on an angle or by removing the side panel of the racks to put them in. It would be great finding racks that worked for them would make life easier.
We have number of RackSolutions shelves (fixed and sliding) for normal racks and they are well constructed.
Never seen their full racks in person however.
The OCP products on that page look more like full OCP racks and ways to mount EIA equipment in Open racks, plus shelves for adding into a open rack, not so much a way to mount OCP equipment in EIA racks unless I missed something?