Hi I received an email last week about "Rack Studs" so I ordered some and they have arrived. Not sure if anyone else has seen or used these but in short they work the opposite way to cage nuts, instead of the nut being mounted in the rack frame the thread is mounted on the frame instead.
I am going to give them a go with some lighter equipment to begin with as they are only plastic however they do look and feel very strong. They are also designed and made in NZ!. Would be interested to see if anyone has been using these.
www.rackstuds.com for more info if my description doesn't make sense.