Kab,
If the excellent felder is a bit too much to afford then you can buy secondhand Startrites, Lunar or even Kity. However the Lunar and Kity will lack something in stiffness and rigidity.
The second thing is that you need to consider the size of the envelope you need for a combi. If you are going to feed in 8ft long timber (2440mm) then you need a 5m long run up to handle infeed and outfeed. Similarly using the planer and thicknesser. The spindle moulder will need at least 1.5 meters in front and 2x whatever the max length of your wood both front and back.
You quickly get to a minimum space of say 5mx3.5m-4m to work the combi.
Third thing is whether you will be using some settings, changing them and going back to previous settings. If so then you will need to find a way to accurately measure the settings on your combi eg some digital scales.
I have a Felder combi CF740 pro which sits in a 5x4m space. Its been excellent as would be the Hammer but I needed to change my working methods and sequencing a little.
Thats why so many people buy separates.....its simpler, easier and can take less space. You probably don't need the spindle moulder right off if ever so a saw + planer thicknesser would work fine and can be positioned alongside each other if needed. Maybe exchange the spindle cost for a used bandsaw eg Startrite.
Hope this helps. I'm not trying to put you off the combi just trying to be realistic