Clausen Nursery located in Vista California carries a wide variety of mulberry trees including Persean Blk Mulberry, Pakistan Purple Mulberry, Pakistan Cookes Select Mulberry, Persean White Mulberry, and Black Beauty Mulberry.
The Pakistan mulberry is a long thin berry with a stem which goes through the entire berry. It has a raspberry/blackberry like flavor with it's fruit getting to about 4 inches long. It is is a dark purple. These trees can get up to 30 feet tall.