After theme loads hook

[Scott Frazer]

Is there some way to hook in extra stuff after a theme is loaded?  I have
several themes I like to use for different reasons, but want to add/modify
faces in them after they are loaded.  I can do this:

(custom-theme-set-faces 'theme-A some-stuff-here)
(custom-theme-set-faces 'theme-B other-stuff-here)

but that only works after the theme has been loaded.  And when you load a
theme, it is automatically enabled which isn't really what I'd like.

I couldn't find a hook in the custom theme stuff, and eval-after-load didn't
work.  I suppose advice might work but seems like a hack.

Any suggestions?
Scott