Sure, I've stuck my Summicron on my CLE -- it works just fine, but of course you have to imagine that the taking field lies within the projected 40mm frame.
I've got the CLE, M2 and M3 (along with various LTM Canons, Nikon S2, Contax IIa, etc.) The CLE is a great camera. One thing really like is that it takes snap-in diopters that also fit the Minolta SLRs of the era -- much less expensive and very easy to use. The CLE finder is excellent, much better than on the CL I as considering buying a few months ago. The CLE meter, of course, doesn't move or pivot as the mechanically-linked meter does in the CL, which to may way of thinking means there's less to go wrong. Plus the meter reads off the shutter curtain/film base and adjusts automatically to changes in light.
Now, I did something to my CLE you may wish to consider. One thing that bugged me was that the meter only worked when the camera was set to Auto exposure. To move to manual, you have to push a small button that disengages a catch under the shutter dial, thereby permitting the dial to move outside the auto range. So when I sent my CLE to Don Goldberg a few years ago, I asked him to disengage the button/catch mechanism. Now I set the camera to auto and use it as such, but when I want to check an exposure and then move to manual, I can just move the shutter dial to the desired shutter speed. This makes the camera more user-friendly, to this user at least! Throw in that you can do OTF flash, if you wish, and the CLE accepts a wide range of dedicated flashes like the 280Px or 360PX, though the latter is almost as big as the camera. The CLE flash is small and great (though mine probably needs a new capacitor, if I could find a repairman who fixes flash units). And the CLE has a "normal" side opening rear door, making loading film easier. Downsides, though comparatively speaking: the CLE is not as solid-feeling as an M2 or M3, but then what is apart from a Nikon F or a Canon FTb? And the CLE shutter makes more of a "clop" sound than a "snick" like a Leica. But I think you'd have to almost be a fetishist to reject a CLE just because it sounds different than a Leica. (For the record, a Leica is loud compared to my Konica IIIa, which sometimes I can't even hear.) I like to use my CLE with a 21mm Voigtlander, the 40mm Rokkor (a heck of a lens), and a 90mm Rokkor. A fabulous travel kit! I've got the a CLE shoulder bag in the box, too new for me to actually use it. But the camera, yeah, I've used it all over the world. Enjoy!