Would you wish to include the export games as well?
I don't think Clay's list is all inclusive.
You could do a year by year search on IPDB and look at only single player games. Keep in mind that "Hearts and Spades" and "Spin a Card" are technically not wedgeheads, although they are both single player games produced squarely (npi) during the wedgehead era. I believe there are just around 100 different wedgehead titles.
Also, keep in mind that some titles listed on IPDB were never produced.