Hey man...I've used an older version in the past but have recently been putting a new one called Xtract CMS through the paces.
Most of the features at a fraction of the cost of the "Big Boys". The Pro version (around $500) even gets you access to the source code.
When I get around to it, I'll be doing a full write up...but it's worth looking into.
http://ecoders.biz