I built my enclosure for a 1000mm xcarve with 30 inches of clearance from the surface the frame sets on to the enclosure ceiling.
I chose this height to have clearance for LED strip lighting, a 4" dust collection hose on a swing arm, an 8" linear z axis, and room for up to 4" of additional lift. Right now I have Charlie’s lift plates installed, and have not yet needed the additional 2" of lift.
I did forget to consider the additional height from adding a larger stepper motor on top of the linear z-axis.
Personally it still feels a bit tight with everything in there. I wish I would have went ahead with 36" of clearance.
Also, plan on placing another access hatch at the back of the enclosure. It helps quite a bit for adjusting belts and just accessing the space for upgrades.
I have added two bays below with a pull-out work table and two stacks of drawers to hold my accessories and a custom controller.