Will there ever be a Vive Tracker lite, or a way to place fixed, or objects identified by patterns in VR?
The Vive Tracker is basically a controller that can be mounted on implements. But not everything needs a full fledged controller.
Body tracking doesn't need a controller. Tracking the body just needs identification of points on the body to be able to create a skeleton programatically.
Keyboard tracking is one of the simplest things to track. It just needs a patterened physical overlay to identify the keyboard, and it's position in space using two or more cameras. Speaking of, why don't the lighthouses have depth sensing cameras to recreate mixed reality?
These are just two examples where a Vive Tracker lite would fill in where a full fledged tracker would be overkill. Simple positional tracking without the other controller options and patterened overlay tracking are only two examples of simple tracking. I'm sure there are more.
I have purchased some kits from Virtual Builds (www.virtualbuilds.com). It's currently not cheaper than buying a tracker, but great for custom projects and developement. I will have some of those projects on YouTube (robawesomevr) when finished!