In my opinion,
First, The Canon EF (does not include FD) is one of the worst candidates for m4/3rds.
- Lenses tend to be rather large
- Electronic aperture implementation makes it difficult to use on m4/3rds
- Focusing rings are not properly damped for manual focusing.
- Like most retrofocus designs, the adapter will protrude more than the Leica M adapters to achieve the appropriate flange distance.
Second, the question is a bit loaded as I'm sure there are examples of Canon EF lenses performing as well (or even better) than some Leica M glass AND vice versa. In the small time I have spent with a 50mm Lux Asph, I haven't seen anything as sharp or as attractive on the E-PL1 or M body. Perhaps if you post some specific lenses that you are interested, some of us can post samples of those lenses on a m4/3rds camera?
Looking at your list of lenses for the R-D1, I see that you've already found some excellent examples from C/V. Have you tried them out on your E-PL1 yet? Some have reported corner issues with any focal lengths less than 35mm... is that a concern?
Mention some specific lenses and someone might post samples. I personally have access to variety of Leica and C/V lenses including 35mm nokton f/1.2, 28mm Ultron (like yours), 12mm heliar, 21 colorskopar.