freestyle milling on a D series?

I bought the D840 right before the M series came out, but I want do some freestyle milling in the future.
Has anyone modified a D machine to do that?
I would like to make a system where I can remove have the bed and clamp something underneath.
Basically what Frank Howarth does on his large machine, but obviously scaled down.

So I would make a table or enclosure where one part could be lowered to any number of degrees ( 0 -90 is probably enough). but that would mean I need to temporarily remove half of the machine bed and base plate. I'm guessing I would need to add additional supports to for strength.

Does this seem realistic or should just sell my D840 and buy an M series (which would

https://www.youtube.com/watch?v=PMo1lJ6XLvA