Yeah. You can boil most of the rules down to "We don't want no flack from other IP holders." With that in mind, you'd be using HMM/MSG and scratch-built stuff.
Basically, Stand River is an event where everyone brings customs in that fit into the Republic or Empire tables, and each custom is worth X amount of points. At the end of the event, the side with the most points wins. It's a cool way to hold a custom contest, and relatively straight forward for points. Last time was a landslide victory.
They also mentioned announcing an entirely new HMM at the event. Will be cool to see what it is!