pcb design software with ability to use pcb 'components'
Do you know any pcb design software where I can design & route common part of design and make it some kind of component?
Altium Designer is a good solution. In Altium's "Recyclable Schematics" - Schematic layouts that you can paste into larger schematics and treat as components.
You can use gEDA's gschem. I haven't tried with gEDA pcb now, but I don't see why it wouldn't be any different from another symbol footprint.
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