Updated
the first post to include a link for the latest release of Sigil (v0.8.6)
Custom-compiled Qt this time to disable the openssl search/load attempt that causes problems when an older version of openssl is placed on the system path by other programs.
Also included plugins that should allow multimedia to work.
In addition to the legacy build, there is also a standard version (32- and 64-bit) that enables multimedia and disables ssl.