These are the only active alphabetic one character accounts on Youtube:
e
h
i
j
p
q
s
u
x
Also:
1 - 9 are also available beside #8, his account is most likely #4 because it has been logged on recently and has no videos but 3000 subscribers.
EDIT: though I look at his post count / reg date after I do this work >_> so its probably just a scammer, owell.