Not that I know of...
The only armband that I know exists for the BB is the one for the Pearl.
BB Cover for Pearl
I was wondering if one exists? I've seen one for the 8100. T.I.A.
BB 8330 w/ SERO Voice Only, BIS, N/W @7pm, Pick3, Unl Text via Credits: $30 +$5 (Unl Incoming) + $7 (TEP)