Lets get the disclaimer out of the way first: What I’ve done is absolutely unsupported by Microsoft. Just because it works for me does not guarantee it will work for you and I am not in any way recommending that you follow my lead!
I use a great many virtual machines for both customer work, internal projects and just tinkering. My ThinkPad X220T is tricked out with extra RAM and two SSDs. Space is still an issue, though, and I can’t squeeze any more storage into my little workhorse.