It's a bit tough to compare our package count to other distributions package counts. Most distributions split one single application into countless smaller packages. Don't quote me as this is a example I'm making on the fly. Packages will often be broken down into foo-1.2.3.rpm, foo-1.2.3-dev.rpm, foo-1.2.3-data.rpm, foo-1.2.3-config.rpm and such. Our packages are all complete. Just foo-1.2.3.tlz, are all rolled up into one. Just as if you had compiled it yourself.
Also some of our packages are actually several related programs combined. For example Gnuchess. If I remember correctly it is made of 5 or 6 chess related programs and dependancies. SDL is another. Several SDL_xxx apps are combined.
So as I've attempted to clarify, comparing package count to other distros isn't easy. Currently our 5.9 repos have a combined count of 1551 packages. But just to screw with your head even more, many of these are dupes with different versions, as packages are waiting in our testing repo, or there are upgrades and fixes as well.
As far as unique packages are concerned. I haven't the slightest idea. The question hasn't bothered me enough to invest the time to sort through all the dupes to single them out.
After all this explaining, I'll bet your question isn't answered. But at least you now know what we know
Edit: Keep in mind we love you guys. You can always request a package that we don't have in our repos, in the package requests section of the forum. Our packagers read these threads and do a pretty good job of delivering.