Thanks for the quick answers!
Right now my main hosting site is on a VPS. It's my VPS, but the hosting is just part of my overall business activities, and my "private" nameservers actually belong to another part of my business
In fact, my hosting business doesn't even have its own WHM!
I'm thinking about an MD-1 just as a testbed, a place to hold one of my sites (dotable nameservers are fine), and a place to provide support if the VPS is down. Does the MD-1 provide a jailed SSH?