There is a method to use a single (heavy) build process with specific provisioning stage based on post-processing (like using only/except based on Post-Processing)?
- vmware-iso (or virtualbox-iso) builder from kickstart/preseed file
- Post processing: ami-export, vsphere, vagrant
The same base image from iso+kickstart/preseed build will be the solid base for every images exported to different providers. Each image will have its own specific provision stage (vbox with virtualbox tools, vsphere VM with vmware tools, etc.).
This make real one image identical for all providers (with only different specific provider needs).