Fred C , Jul 01, 2007; 09:58 p.m.
If you really mean Contarex lenses made in the 1960s and not the Contax SLR versions from the 1970s onwards, there are no adapters made for them. Zeiss Jena M42 lenses are easily adaptable though.
What's your budget? The Canon 5D is currently the most affordable camera with a 24x36mm sensor.
No one knows exactly "what models might be produced in the next 2-3 years." Entry-level DSLRs will still have APS-C sized sensor (about 24x16mm). There might be Canon 6D that's more affordable than the current 5D.
The 4/3 system has a sensor with the aspect ratio of 4:3 (duh), as opposed to the traditional 2:3 ratio derived from the 135 format. Because of the sensor size, 4/3 cameras have very small viewfinders and there is less control over DOF.
Spend some time here: http://www.dpreview.com/reviews/specs.asp