If you're going to use the (->) Monad instance, why not:

  {-# LANGUAGE MonadComprehensions #-}

  import Data.Maybe (fromMaybe)
  import Data.Monoid (mconcat)
  import Control.Applicative ((<*>))

  pam = flip map
  fizzbuzz i trigs = pam [i..] $ fromMaybe . show <*> mconcat . trigs
  
  ans = fizzbuzz 1 $ \i -> [["Fizz" | i `rem` 3 == 0]
                           ,["Buzz" | i `rem` 5 == 0]
                           ]
  
  main = mapM_ putStrLn $ take 100 ans