Jason,
The new LR4 version offers lens corrections for M lenses - mainly the modern versions. But more to your point of setting up defaults there are two ways one via an external product, Xrite ColorChecker Passport, which in my opinion, does a fantastic job in profiling your camera. Or you can get a sample image process it to your liking and save it as a user preset. If you create a user preset, you can use this preset as you import the images.
If you are shooting an entire job under the same lighting conditions, you can import an image adjust the levels, color balance, sharpening etc, save it as a preset and apply this to the rest of the images on import. Once imported, you can tweak the images as needed. Almost like doing a snip test for film.
Using the ColorChecker Passport, you can create a profile for the camera either for a particular job or for general shooting purposes. I have found it useful for profiling the M9 under low light conditions and found that the noise level is reduced to an acceptable level at 2500 ISO. These profiles are saved to LR as a custom profile in addition to the standard Adobe and embedded profiles.
I migrated from Aperture to LR about five years ago and at the time found that Adobe LR was a more universal product than Aperture. While I did like the interface that Aperture had, developers were more inclined to put their efforts to the Adobe products.
