We are also combining FIAR and CM - I have a 4 and 6 year old. I am transitioning into the CM part now and it's working great. We are planning on replacing the Literature portion of CM with the FIAR reading/activity, and then tacking on poetry, nature, hymn, and music studies, as well as math (we are using Math U See but hoping to transition to Math on the Level), Apologia Science, Egypt through Deuteronomy handbook/curriculum for Bible/History/Geography, Spanish exposure through cd/dvd, A Child's book of Character building (1 story ever week, so 4 wks per trait (48 wks total), this we will start early and end late as we are adopting the CM (3) 12-week terms), Pathway readers (my 6 y.o. LOVES this!).
For FIAR, I am planning on 2 weeks per book, using it 3x/week (read and one activity). My girls have loved looking through their lapbooks this year so I thought by spreading it out to 2 wks per book that we would have time to do the lapbook activity along with all these other subjects we have added through CM. For Kindergarten, we did strictly FIAR+math+phonics, and for us that was enough. What I've outlined is probably a bit heavy for K, but to answer your question, yes, there are others combining FIAR and CM, and it's an easy transition to add the CM suggested curriculum once you are doing FIAR.
I am curious if anyone does Five in a Row AND the literature for CM... how are you fitting all of this in???