Yeah, that works quite nicely.

Regarding the floor location: no, it doesn't exist in Bukkit already - consider for example the hit box of a flower.  Its floor location's Y co-ordinate is the block's base Y co-ordinate, but the X and Z co-ordinates are somewhere in the middle of the block.  For something like a sign, the floor co-ordinates also depend on which way the sign is facing.