Interesting, and thanks for the feedback. Much appreciated.

So, is the supported round rail really that loose? I'd like to say that I'm okay with babying the MRR, but I know that will grow old sooner rather then later so I am certainly looking into profile rail.

I basically scaled down the design idea from a Mazak that I run pretty often, and love. However after a few hours of looking more into this I'm beginning to wonder the following scenario:

Build a "cheap" heavy duty router in the style listed above (with round rail) for the decorative work that doesn't require anything tighter then 0.3 - 0.4 mm or so. This will allow me to expand the X & Y and reduce the Z and worry a bit less about rigidity...
meanwhile...
Build a stout metal mill. Classic vertical mill, stout "L" shaped base with minimal throat and reasonable X & Z travels. Most of the metal workpieces in mind require no more then a 100 x 100 x 100 (mm) cutting envelope. This, with some more thoughtful table design will allow me to "justify" the profile rail expense, as most other components will be the same or less actually. I'll basically save this for the aluminum, brass, and the super rare carbon steel parts.

Granted it is at least a good excuse to have two machine tool projects. The wife will understand I'm sure