jman: I make my tables the same way. I have them taller than a "normal table height" so I can work on stuff without bending over too much.
I also made two that were 2' x 5' (I have a 24" plotter, so it fits my output). I drew a 1" grid on the surface and cover them with .25" plate glass. I can clamp them together to make a 2' x 10' table. I use these tables all the time for weeding and masking vinyl (I have a home-made transfer tape dispenser at one end). Also great for painting small things because you can scrape the paint right off. I use the glass as a palette when hand painting.
If anyone is interested, I can take some pix and post them. I have been in dozens of shops, and my el-cheapo set-up is the most convenient I have ever seen. I really can't describe the tape dispenser other than I use the plastic "end caps" that come with Arlon vinyl, threaded rod, and wing nuts. I tension that between two of the legs that extend up beyond the table top. I can adjust tension with the wing nuts. Works really well for me, and I can do longer than 10' with one piece of tape if needed. The whole affair is a couple inches higher than the Webermade dispensers I used to use. I find my home-made set-up more adjustable and easier to do longer runs.
All my 4' x 8' tables are on wheels, and are the same height so I can configure them as needed.
We have a base made of EZ-Rect commercial shelving which provides 2 shelves of 4x8 and the top (3rd shelf) originally was 4x8 but I purchased a 5x10 sheet of 3/4" plywood from Windsor Plywood for !50.00 Canadian $ to fit over top, in order to fit on the 4x8 frame underneath I simply screwed 2 of 1"x4"x8' planks to bottom of 5'x10'plywood and repurposed the original 4x8' plywood. On top of that I placed a 5x10' Rhino cutting mat. When it was 4x8 I used Puckboard but found the blades wanted to follow previous cuts. I've also used glass on a smaller light table but I find the blades dull much quicker. In my opinion a cutting mat is by far the best and preferable to add even to a light table used for cutting. The Rhino mats are quite thick and I expect I can use both sides if I ever wear one side out.