so far in my short japan trip only seen typical garden varieties of kei wagons/hatches.. as well as honda beat, suzi cappuccino, alto works, copen, mira turbo, subi rex.. havnt yet spot mazda az-1..
theres some article on autospeed "kei fun" ... not sure if this link will work..
http://66.102.7.104/search?q=cache:iSoctnd...appuccino&hl=en
there are plenty of shops that specialise for kei cars such as:
http://www.palsports.co.jp/
F6A should be fairly easy to go in the alto engine bay.