Mill recommendations needed for new CNC Project

I'll be approaching my Boss on the possibility of putting together a
small CNC Milling Station.
Our need is quite specialized and it might be better suited if we
build our own. I know a ready made commercial machine will be out of
the question. All of our in-house CNC Machines are tied up in
Production or tool making.

So I'm asking you-all on your recommendations on a good new starter
Mill that could be converted. Would like to keep the Mill price around
and under $2500 (new). I'm figuring another $1500 for other parts.

For my Home Shop, I converted a Grizzly (of the rong-fu type design).
Although it's perfect for my hobby use, It would just not be tight or
beefy enough for our application. And of course, you-all know about
the round column problems.

We often design Forming Dies (two dimension) for various types and
thicknesses of spring steels.
The results of bending a part, often, is not quite as expected
(calculated) and will fall out of tolerance, so the Die needs to be
reworked or remade. The second try is usually successful.
Most of our Dies are EDM'ed by an outside source, and can be expensive
and most importantly, time consuming.
I believe I can justify the concept of a small in-house CNC for this
purpose only. I would not expect nor want the Machine to be used in
Production.

My Maximum Milling Envelope would be: X=6" Y=3" Z=1".
The Typical size of a Die is 3"w x 1.5"h x 0.25"thk. with a profile
along the 3" dimension.
Most of the time I would be using an 1/8" Mill in 0.125 - 0.25" thick
material. Typically "O1" or "D2" tool steel. (Annealed of course)
Probably use Servo Motors, speed is of no importance, so Step Motors
might be OK.
Dual Nut Ball screws mounted on Annular Bearings for Minimal Backlash.
Will be using Gecko Drives, a Brute Force Power Supply, Computer
Interface and a Computer running Mach3.
I found that the most difficult part of converting the grizzly was the
Z-axis, so the basic machine should be well suited for that.
The converted machine will be CNC only with no manual operation.

What did I forget?

Thanks in advance for suggestions, support and???

Tom M.