As others have said, you can buy the R3A & then buy the 40 Summicron-C separately to mount on the R3A. The lens is interchangeable & can be used with any M-mount body.
Among cameras with 40 mm frame lines, you also have a third alterternative - the Rollei 35 RF, essentially a mechanical version of the battery-dependent Voigtlander Bessa R3A, as both of them are built by Cosina, but without the AE feature & 1.0x viewfinder magnification of the R3A. Although it can be purchased as body-only or in a kit with its own Zeiss designed Rollei 40/2.8 Sonnar lens, like the other 2 cameras can be used with any of the four 40 mm lenses available & it is in the same price range as the other two you are considering.
It's interesting to compare the range/viewfinders of the 3 cameras because this is the most significant difference among them. The R3A has a 37 mm base line with 1.0x magnification, or 37 mm effective base length. The Rollei 35 RF has the same 37 mm base line with 0.7x magnification, or 25 mm effective base length. The Leica CL has a 31 mm base line with 0.6x magnification, or 19 mm effective base length. The Rollei & the R3A share the same exceptionally bright viewfinder.
The R3A's longer effective base length offers the most accurate focusing of the 3. The trade-off is that due to its high magnification, the 40 mm frame lines can be difficult to see for some & almost impossible for most eyeglass wearers. The Leica CL with its lower magnification offers considerable eye relief & the frame lines are easier to see. The trade-off here is that the combination of lower magnification & shorter base line mean that focusing is less precise, which is a more significant factor with longer lenses & fast normal lenses. The Rollei 35 RF is a compromise between the two: 40 mm frame lines can be seen comfortably by eyeglass wearers & the effective base length offers greater focusing precision than the CL but not as great as the R3A.
If you decide to buy the CL, a good source is
www.sherrykrauter.com. Sherry is a Leica-trained technician, who sells some of the Leica bodies & lenses she services. Although there is always the ebay route, a camera purchased from Sherry will be checked by her before she sells it & serviced by her if it needs it.
Good luck.
