If you guys insist on attaching foreign pieces of glass to your 20 pancakes, why not try this one on for size:
The original Panny DMW-LW46, which attaches via a separate adapter tube to the Lumix LX3, yielding an 18mm f/2, will screw directly into the Panny 20mm f/1.7 pancake, as both lens and wide converter are 46mm. Being a .75x converter, it'll yield a very useful 30mmf/1.7 moderate wide. Profile is not too bad either, as it's flared but small, conferring a somewhat retro, archaic appearance on the entire rig.
I tried it and was thrilled with the optical results, till someone on the dpreview threads pointed out the danger of burning out my focusing motor. You'll find it's not all that huge a mass, but I take no responsibility for damage to your equipment. And keep in mind, if you think using it only in manual focus mode will eliminate any hazard, that the focusing motor still seems to be utilized for some kind of "focus assist," even when you're manually focusing