Don't let height get to you. Cosplay whoever you want..You mention DBZ, so....Whether you wanna cosplay kid goten or trunks, or freaking Cell, do whatever you want. If height for whatever reason is THAT bad for yo (again, don't let it be) then there are plenty of characters in DBZ as well as mentioned Ryuk and Rem who, as shinigami, are both very tall.
Cosplay DA Regular DA
-Fate Testarossa (Mahou Shojo Lyrical Nanoha A's) ~90%-
-Ryouko Ookami (Ookami san and her 7 companions) ~75%
-Amy Sorel (Soul Calibur) 25%-