Ehm, Kixforms Classic works fine for me on Win7 x64.
Place kixforms.dll in %WinDir%\SysWow64 and register it using regsvr32.
Using version 2.47.4.0 btw.

KixForms.Net works fine for me as well, I've switched over to it ever since it came out.
Using version 3.2.14 of that, which works on .Net 2.0