I can get this added into the gold version as a Pro Only feature. I think 30 is a bit to much, but, it will have two settings in DragonByte Tech: vBSuper PM's - General Settings one for turning off the block , so it don't show in the ACP, and another to select how many latest PM's to show.
No, I wont be adding the contents of the PM in that table, it takes up too much room, and ability to view the contents of the PM is already available in the PM Log.