Here is my field point target. I bought it about 14 years ago. There is no telling how many arrows it has stopped. The front material is ready to finally be changed. It would be easy to make and I highly recommend it. The dimension on this one are 4'x4'. You could definitely make it larger or smaller. I have put casters on the bottom of it to make it easy to roll around.
I shoot in through my garage door to the opposite side of the basement which at the farthest point is 18 yards.
There is no stuffing in between the two front layers (the layers around the 2x4's) but the 6x6 back layers there is pillow stuffing stuffed in between them very tight. It still shows no sign of needing replacement and arrow penetrate about the same as the day I bought it. Not sure what the material covering is but I'm sure you could find anything similar to use.
A real plus to this target is the different layers that the arrow passes through allows for them to remain perfectly straight just like they go in which keeps you from breaking arrows as you shoot at the same spot.
Hope this is a benefit to someone.