4th and/or 5th axis head

The March 2000 issue of "Modern Machine Shop" has
an article on a 4th & 5th axis rotary head retrofit for
existing mills from Tri-Tech Precision Products.

However at 150 lbs and $50K it is probably too big for
our machines in the basements & garages!

In any case, has anyone experimented with a 4th
or 4th&5th axis attachment on the Z axis?

If not, I'll bet there are a bunch of "ideas on paper"
for such beasts. Also, can it be accomplished by
any other way than a turn & swivel arrangement
(like the belly turret machine gun mount on a B17?).

Also, the software to drive it is a bit expensive,
but when there is a will there is a way!

Doug Fortune