It seems to have been done before.
The version I'm thinking of contained something like:

Down the lane I look and there crawls Mary
Hair like gold, and lips like apples.
It's good to smoke...
...
Down the lane I look and there lies Mary
Hair like gold, and lips like watermelon.
It's good to smoke...

But, this is what I found
the boogiemen - smokin' the green green grass of home
http://www.youtube.com/watch?v=Z9-MiISa_gg