Personally I definitely wouldn't go down the RAID-0 route for this, not unless you really need a single large volume to store your VM's rather than splitting them across the disks.
Since you're talking about having multiple VM's running on there, if you plan things well then realistically (especially considering the spec you've listed) you're going to have more than one VM running at a time, and can split them across the SSD's to balance
the Disk IO requirements, therefore negating more if not all of the performance benefit you would have seen from having RAID-0.
In addition, yes it's only a lab environment and you can re-build it, but that's still a lot of additional hassle. Having them as separate volumes lets you split that risk, so if one dies you've only lost a quarter of your data.
I'd go with keeping them as separate volumes, put the host OS only on the boot disk (and perhaps use the rest of the space for things like ISOs etc) and then split the VMs across the remaining three.
