One thing that I've noticed over the years is that.... the less you try to get by paying a model, the less likely the model is to show up. I saw this quite a bit this past year when I was shooting with Twistys. In most cases...the models that were paid at or above the standard rate for this area - always showed up for their shoots. In contrast.... the girls that we negotiated lower rates for, were more likely to not show up or cancel at the last minute. This is just an observation on my part and of course it's not 100% true in all cases but for the most part - that's how it usually plays out.
Also, I feel that hiring models that are represented by respected agents or agencies are more likely to show up than a model who is representing themselves...or a model that was found on OMP, Model Mayhem or even Craigslist.
Your best bet is to move to a place where you can work through agents or agencies or just get used to having a large number of no-shows.
Good luck!