This is pretty basic, but wanted to show something I was up to. I hunted down the Army Issue cold weather / watch cap and modified it to be a solid patch platform. These are quality comfortable caps that are 100% synthetic, microfleece, no-pill POLARTEC 100.
The loop velcro area is 4" wide x 3" which allows for mounting of many patch shapes. The edges are sewn with a serger style stitch so there are no snags when brushing by the velcro. Comes in one size and available in Black, Foliage, and Coyote colors.