Hi Jim,
The largest commercial font we have is AdobeSongStd-Light, which is an Adobe-GB1-4 OpenType font that has 29,064 CIDs (glyphs). Unfortunately, it is not a font that we sell outright, but instead is bundled with several of our applications.
The largest font that I have built was used to produce Appendix G of my book ("CJKV Information Processing"), which is a complete CNS 11643-1992 character set table, arranged by plane. That font has 55,880 CIDs. I never built an OpenType version, though. Doing so would not be difficult, but there would be little benefit in doing so. It is not a commercial font, which is the reason. If you are interested in such a font, I suggest that you contact Arphic Technology. I can provide contact information if you need it.
BTW, I have analyzed Founder's font, and if you'd like to see that information, please contact me offline.
-- Ken