1. CadCut CNC Plans - Heavy duty CNC machine. 4'x8'x9". Excellent!
2. MachineToolCamp - Different sizes of CNC machines. Nice lightweight machines. Step by step instructions. Easier if you use parts sold by them.
3. Data-Cut - Nice machine. Plans rely allot on CAD drawings.
4. Campbell Designs - Nice moving table CNC machine.
5. Jeff Davis Drill Mill - Drill Mill plans.
6. The Zoltar Machine - Plans for a small cnc machine.
I'm sure there are some others. But these are the ones I know of.