Hi ochsiong,
I'm using the Lumix-Leica 45mm f2.8 Macro lens on my Lumix G-1. You can see some shots that I took last Saturday with Jacobs group in AMK Park with the link below.
http://www.clubsnap.com/forums/showthread.php?t=788300&page=4
The photos may not compare too well with the other sifus using high end Canons, but I think it is more of my lousy handling rather than the G-1 cam & lens. I'm quite new in dSLR photography and macro, just started last Nov. This is my 5th macro outing with CS groups. My hands are not that steady with hand-held (hey - I'm an age 65 grandpa!). I think the Leica 45mm is all you need. You don't have to add extn tubes or Raynox at all. The Leica lens is "mou-tak-teng" man.:thumbsup::thumbsup::thumbsup:
Cheers.
LEW