Mounting a server by only its ears

I don't think I'd be comfortable doing that either. We use Two post Rack Shelves to help support 2-4U server in 2 post racks.

If you are unable to find something suitable you could try asking Dell even if it's just so you can kill an hour or so trying to get through to the right person. Failing that check out some of the smaller "engineering" or metalworking companies in your area. They're trivial to make (cut, bend, drill) and shouldn't cost too much.