you can get euro bb for 19mm or 22mm spindles. you would have to check on the spacer situation and you might have cut one or use a pipe. you would want to be as precise as possible so that the inner bearing race is supported. i guess nearly any bmx crank could work. look at bb, cranks, etc at
www.danscomp.com too
this place seems to have some cool cranks:
http://www.gussetbikes.com/gusset/viewcat_mtb.php?i=BBs'n'Cranks
from danscomp:
etc...