Configuring a test box with multiple VM's

[techlists at phpcoderusa.com]

Hi,

I'd like to configure a test box for LAMP development.  What I have in 
mind is setting up multiple VM's on the box and loading a different 
distro in each VM.  Probably only need 2 or 3 VMs. The number might grow 
over time.  Will not be configuring X on any of the VM's - they will be 
LAMP servers only.

I seem to recall someone saying I would need a base system on the box 
and then load the VM's on top of that.  Or can I use something like Mint 
and load the VM's on top of that?  Is there a disadvantage to doing it 
with Mint as the base system?

The box is an i3 with visualization  - 
http://ark.intel.com/products/81018/Intel-Core-i3-4030U-Processor-3M-Cache-1_90-GHz 
  It has 4GB of RAM which I assume might not be enough.

This box will only be used for testing so I assume each VM will only 
need 1GB of RAM and will probably use much less.

Any direction is much appreciated.

Thanks!!

Keith