Found on ESPN’s BMX site: Bicycle Union has released new 2Z shin pads, which are as appropriate for freeriding as for BMX, based on the old-skool Hammer 2Z pads from the late ’80s.
They’re made of neoprene with dual plastic strips for protection and wide velcro pads to keep ’em attached.  They only come in black, and are available in small, medium and large sizes.