I am petite and had the same issue. I decided to first try the seat harness instead of a waist which helped a ton; next I invested in the Naish Women's specific bar which I use with my Kahoona kites and it is easy to reach the depower and I actually took the stopper ball off to get the perfect throw. If you don't have the extra cash for a new bar, start with the short CL which Naish also sells. The shackle looks neat tho.
You can shorten the throw on the North and Naish bars easy enough, check out there individual webs sites the info is there. We did exactly this on both bars and it worked out well for my partner and her short arm reach
also, the Slingy bar has below the bar deposer so you can always reach it and a smaller chicken loop as well. So with a seat harness or preferably a shorts harness and slider bar it could work quite well. And the 2014 Slingy is really easy to adjust even though it is below the bar.
you can also adjust the bar position using the knots that are in the power lines (usually 5). Set it back maybe 1 knot (that will give place the bar an inch closer to you) and then trim the kite using the depower strap..