Do you have any idea what to use in the middle to keep the coat stant at the shape I make it?
This is probably similar to one of the ways to make the tri-bolt for Chris Schwarz's folding camp stool, as shown below.
Basically, you need a central hub for all of the bolts/screws to connect to, and the stand uses this hub as a pivot point when it spreads out.
If you wanted to make it out of metal, you could buy a section of pipe, cut off a short segment (like 1/2" to 3/4" long) and drill and tap the holes for as many vertical slats as you want. Thicker pipe is better for this application since you want the bolt to have as many threads engaged as practical.