Have been noodling with the design and have made more changes:
1. I lowered the gantry by a foot so it doesn't look so tall now. Reduced weight and cost too. :-)

2. I was shopping around for aluminum for the uprights and found some 1 3/8" that I was able to get cheaper
than I would have paid for a 1" so I will be using a much thicker upright.

The first attachment shows the redesigned gantry.

The second attachment is the completed frame. To make it easier to mount the rails, this was assembled
upside down. I then had a friend help me turn it right side up.

The last attachment are some parts for the x-axis. I milled channels in them to make aligning the parts easier -
easily the smartest decision I've made on this project. :-)