Welcome to Sphynx Lair. You found a great site to start your search as Sphynx Lair has an active rehoming board. You could also contact breeders in your area who may be looking to retire kitties from breeding or showing. The key to finding the right Sphynx is a lot of patience coupled with lots and lots of research. Good luck.
Check with Specialty Purebred Cat Rescue, Search Results for "purebredrescue.org" out of Milwaukee. I adopted two adults this past June from them and I know that since my adoption they have listed more adult Sphynx kitties.
Check the listings daily and if you see a Sphynx act fast! They are in demand.
Good luck! They are amazing creatures--slightly otherworldly yet completely loving!