Hm... do you mean tapping as in travis picking... ala jack johnson/jason mraz.... or tapping like speed tapping? I don't speed tap at all on my acoustics... i do travis pick quite a bit... (travis picking is when you get the popping sound when you slap your fingers on the strings... gives it a percussive sound).... For percussive acoustic guitar I highly recommend going with an interior mic rather than a pickup.... A mic will pick up the full range of sounds better than a pickup. The pickup will only pick up the noise that's transferred through the strings.

Can't really think of any guitars down around 400 bucks off the top of my head... But check out Breedlove, Alvarez, and Takamine guitars. They have a wide range of guitars... Alvarez and Takamine have guitars in your price range.... Breedlove is a more pricey brand... but they're great guitars.