I would be kind of surprised to see more then maybe an odd random model or 2.
You can usually get by without it though with a little effort. The case panel connectors are usually small enough to fit directly under the board in the space the standoffs leave you pretty easily. The power supply cables can be made to work in this fashion as well. With cheaper PSU's, just cut the zip ties as necesssary that keep the individual wires bundled to sorta spread them out / make them fit directly under the board too. For better PSU's, cut the jacket off so you end up with the same loose individual wires. Just get an idea from where your connections are as to where you want the wires to go under and come back over the motherboard, lay em down, throw on some strategic tape to help things stay in place while being installed, then mount the motherboard. Probably not the most ideal method to some people, but I have done a few machines like this that had absolutely 0 option for decent cable management, and had great results.
