County Supply has advertised SEI certified Helmets
for only $18.95 right now (sale ends 5/31)but no yellow....only comes in
blk, purple, blue, hunter green and good old white...maybe buy an inexpensive
helmet and have it painted to what you want? That way you can see if
it looks good before buying an expensive one and trying to have it
painted. I don't know how that would work as the color in plastics
is normally put into the plastic prior to the mold...I haven't had much luck
with paint sticking to plastic...but they do paint corvettes and they are
kinda made out of plastic right!? (well fiberglass I know, but same
difference). As others have stated it may void any warranty though....I
know you didn't want a helmet cover....but that might be your best feasible
opportunity to get the color you want. Good luck with your
search!