We have a similar set-up - ours uses a large metal frame we put together from parts of a modular exhibition display that I bought in a moment of madness, but it could easily be constructed from timber.
The gubbins are inaccessible without dismantling parts of the table, and I never photographed it whilst putting it together, so I'll have to tell rather than show + diagrams.
It's a ~1m^3 cube with an additional, continuous, cavity underneath (40cm), behind (40cm) and on top (~15cm) that each contain 10 evenly-spaced Osram Lumilux Deluxe 954 fluorescent tubes (so 30 in total - wired to three plugs so they can be operated in blocs) on mounted reflector battens. The outsides of the cavities are boxed in to prevent light-leakage.
The cube is floored with 1m^2 of 25mm clear acrylic, which will take very heavy items, and then a continuous ~3m length of translucent matted film - the type used to print back-lit posters on bus stops and in cinema foyers - is tacked to the top, the back and the floor with double-sided tape, leaving quite a loose curve where it meets corners to avoid jarring lines and shadows from the cube's frame (it's called an infinity curve). The floor is then optionally topped with a 2mm sheet of acrylic (matted/frosted on one side) to protect the film and/or create a reflection (although the films are easy to replace when they get worn) - but this will create a line at the back of the cube where the acrylic refracts shadow, and will need to be 'knocked out' with a couple of GU10 5400k LED spotlights mounted to the front of the cube. They also come in handy for highlighting gilt, enamelling and signatures. If you're only photographing small items, you can also negate it using depth of field with your camera.
Suspended inside the cube on thin wires running parallel to the front opening of the cube are two 'curtains' made from stiff black fabric (I cannibalised a cheap roller blind and stapled the fabric around stripwood at the top and bottom for rigidity and weight) that can be pulled as near as you need to transparent objects to give them something to refract. They're suspended on hooks, so they can be easily removed/replaced.
Opaque items with fiddly shapes might need an additional light source at the front (we've a cheap soft-box on a boom stand), but generally enough light bounces around in there as-is.