if there is any truth to the rumor that SSR is nearing a sell-out
They have about a year left to go at SSR.
...and assuming that the sales rate for AKV will end up being 'faster' than that of SSR because of a higher interest level among non-members...
That's a pretty big assumption.

According to stats posted here, SSR was actually selling at a rate about double the pace from 2000 to mid-2003 when SSR was first offered. While every resort will speak to different people in different ways, I think it would be a mistake to simply assume that AKV will sell faster than those that came before just because of a little Internet buzz.
...as well as the fact that AKV will have fewer units to sell...
Fewer units but with many of the rooms having higher nightly point requirements than SSR units, it's not exactly apples-to-apples. AKV will have less than SSR to sell, but not the number one would thing when looking solely at the number of units per resort.
Also, there's always the possibility of DVC expanding further at AKV. SSR was originally supposed to have 12 buildings and later grew to 18. Can we definitively conclude that the same won't happen at AKV? Unless I'm mistaken, even after the DVC room conversions, Jambo House is still the largest cash resort in the Deluxe class. Taking the 5th and 6th floors for DVC was a convenient cutoff point. Perhaps the 4th floor will be next.

Another factor you didn't address is other DVC developments. SSR has been the sole resort offered for sale practically since it was introduced. In light of persistent rumors regarding Disneyland and off-site developments, either of those projects could severely impact sales of SSR and AKV. Certainly they would open up new markets, but we have seen hundreds (thousands?) of members buying SSR and AKV points from the California sales center. In my opinion, sales of WDW-based points to west coast members would drop to near zero if they start selling a DL-based resort in the near future.
Construction time for the DVC CR (if that's what it is) is also an unknown. It took them over 6 months just to demolish the old structure (started in September, finished in April). They don't appear to be in any big hurry to complete whatever it is they are working on. It took Disney 2 1/2 years to open the first units at Saratoga Springs. That included re-using portions of the old Disney Institute, and features guest buildings that are only 4 stories tall. How long will it take to construct a 15-story tower, particularly given that the property is not as accessible as others on Disney property?

Depending on a lot of different market conditions, it's not totally out-of-bounds to think that they might be selling CR by 2009, but I can't see the facility opening to guests in '09.
...it's not THAT long to wait - especially considering that the CRV rumors have already been flying for what seems like years!
Oh, it doesn't just "seem like years."
