It can be done BUT you HAVE to book online right at 8:00 am when your 7 mo. window opens up.
We were able to book an OV studio for early-mid August 2013 which we ultimately had to cancel. When I started looking into re-planning the trip for about 30 seconds we considered spring break this year (specifically the week leading up to Easter) and Aulani was wide open - and for awhile too 'cuz out of curiousity I watched it a few times because I thought it was curious that it remained open. We decided to pass on that option tho for several reasons. One being that with the time diff. we would ONLY have 7 nights PERIOD for the trip and we wanted to island hop - esp. for the cost of the airfare to get there. We wanted at least 10 days in Hawaii. So then another reason was the airfare - it was ridiculous for Easter. Finally, it would've sucked down a lot of points for that "season". It just didn't make good use of our time, points or money to try to go over spring break. We are now re-booked for this August. We didn't have as many points to "spend" this year tho so grabbing an IV studio was important to us this time around (last time we had the flexibility to book an OV). We got it but before the day was out all of the studio categories had spotty availability. Actually, it was spotty by mid-morning and the IV was gone right away.
Good luck!!