It looks very close to
Acer palmatum 'Shishigashira'

Here is a link to compare your tree with other. There are two forms of this type of cultivar, One being not quite as crinkled and a little larger leafs. I think yours tree fits 'Shishigashira'

http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=2209

Mike
Acer palmatum 'Crazy'

i am pretty sure you are correct ...

i got it from a guy who go by the name shishi ... and i recall getting a tiny little plant from him with that name .. it all fits.. thanks .. ken

Ken: Welcome to Mapleland......Shishigashira is a beaut-wait till you see the fall colors.....

Koniferkid

Definately looks like A.p. 'Shishigashiri', also called the Lions Head maple. I've got 2, even smaller then yours. Considered a dwarf, hardy, with great fall color. Good luck,

Dave

Ken, my neighborhood rabbits love my 'Shishigashiri' so I have to fence it or it will be a stick come spring. Come to think of it, rabbits love Acers like deer love hostas.

Ron