I was wondering if you had room for one more.
If not as a student, then I can settle for some highly skilled Mercenary or something...
Anyways, I love the RWBY series. Been following Monty Oum since Dead Fantasy, and Rooster Teeth since, of course, Red vs Blue.
Well, we currently have seven students. With groups of 4, that means one more makes an even eight; two full groups. Hotaru did mention making a character, but she has been quiet since then; for good reasons, I imagine.
Taking that into account, I'll still say it's fair for you to do what you want. You could be an eighth student, which is really needed, or, if you prefer, you could be one of the following:
A) A trained Hunter assigned to the Schwarz post (those Hunters will be plot centric, so it's easy to work a PC one of those into the story)
B) A teacher at the academy (we're short on staff, at the moment, so this would actually be my preference for you or Hotaru)
C) A native or non-native that has taken an interest in the Mist phenomena. They may or may not be trained as Hunters, but should have combat experience of some sort, to keep them viable.
D) Make a suggestion!