So the question is, how screaming is that deal on the Ocelot? If it's really all you can afford, then get it. But it's not as good of a boat as the WD. In fact, the design of the current Ocelot was one of the first prototype designs of the WD. I got a chance to try it on the NF Payette in the summer of 06. It was a big improvement over the existing Ocelot, so AIRE put it into production immediately as the new Ocelot, and kept working on the WD.
My dad just sold his Ocelot because we have two 14' WDs and a 13', and there isn't any reason to keep it. There's nothing we would do on the Ocelot that the WD doesn't do better. If you want to have a smaller boat and a medium boat, the choice should be 14' WD and 13' WD, not Ocelot and 13' WD.
But back to frames. You will want to get a bigger boat first if you're sticking with an NRS frame (for now), because AIRE's d-rings are a little higher than other designs.
Of course the ideal situation would be to get a new WD and new frame all at once, but that might not be financially wise, depending on your circumstances. But there's no reason you'd need to start with the older design and work up to the WD. The WD is simply a better boat in every way.