Yeah, that's definitely possible; I do it all the time. If you're hanging fixtures from the truss itself you need to make sure that they are capable of being mounted sideways. A lot of Elation movers are not built to be side mounted. MAC250's are okay. I would suggest clamping a pipe through the truss and mounting the lights from the pipe. This way you'll be hanging them upside down (which is acceptable for all moving lights). As Josh mentioned, try to distribute the weight evenly. If you're looking at putting one on top of the truss I have found that a Mac250 will sit perfectly on top of standard 12" box truss. The feet of the light fits right into the opening of the tubes. I use a bungee to secure it, go through each handle, around the truss, and connect the bungee to itself.