R – Automating VMWare or VirtualPC

I've not used Fusion, just workstation and server

1) Yes, you can create a linked clone from current vm state, or from a saved state (snapshot) in VMware Workstation

2) Yes, revert to snapshots

3) There's a number of different network setups, NAT's one of them

4) VMware virtual machines created with VMware Fusion are fully compatible with VMware’s latest products.

5) ?

6) You can add pre-existing to disks to other vm's

7) Yup, you create multi-cpu vm's

Workstation costs, but VMWare Server is free

Sorry to deny anyone an accepted answer here, but based on further research (thanks to your answers!), I've found a better solution and wanted to summarize what I've found.

First, both VirtualBox and VMWare Server are great products, and since both are free, each is worth evaluating. We've decided to go with VMWare Server, since it is a more established product and we can get support for it should we need. This is especially important since we are also considering distributing our software to clients as a VM instead of a special server installation, assuming that the overhead from the VMWare Player is not too high. Also, there is a VMWare scripting interface called VIX which one can use to directly install files to the VM without needing to install SSH or SFTP, which is a big advantage.

So our solution is basically as follows... first we create a "vanilla" VM image with OS, nothing else, and check it into the repository. Then, we write a script which acts as our installer, putting the artifacts created by Hudson on the VM. This script should have interfaces to copy files directly, over SFTP, and through VIX. This will allow us to continue distributing software directly on the target machine, or through a VM of our choice. This resulting image is then compressed and distributed as an artifact of the CI server.