Ah, i think I've found your solution. The gentleman in your supplied video describes the "Glass Coat" resin as a water effect, which would be a typical 2 part resin that dries clear.
Jump on Google and type in "Water effect resin +
40k" and check to see what people have to offer. I've never done much with the topic myself, but plan on a few different ideas.
But, here's a good cheap idea for ya. I know that water effects for miniatures will cost quite a lot (everything for this damn hobby does

)
Go down to your local Advance Auto, Napa, Autozone, Walmart, etc, and check out the pourable resin they have there (typically sold in 1gal. containers). If you can't find it, look for Fiberglass (just don't add the fibers, it's resin! If you're nervous, ask a store associate). Usually used for autobody repair and whatnot.
*Remember that all resins are 2 parts. Ensure that you have both parts in hand before going home.
The stuff dries clear, and is pretty tough. You're not looking for extreme detail so that's no big deal. Do a little test piece to see how ya like it, and go from there.
If you choose to try another type of resin (local hardware store: Ace, Home Depot, Lowes, etc) get yourself the type of resin/epoxy that dries in 24hrs. That way, you've got time to play with it and not have to rush (can't rush perfection!). Take into consideration the time it will take to paint on the clear coating, then stipple appropriately. Again, do a little test piece first to see what kind of results you get.
Otherwise, same steps:
1 Brush it on
2 After the whole surface is covered stipple with a ball of paper-towels
3 BAM SUCKA! Awesome playing surface.
I will highly advise that you have good ventilation for this project. Resin in small quantities can wreak havoc on your senses, so this large of a quantity.... And, attempt to do it in a clean environment. You don't want your awesome project catching dust, do ya? Once it's in there, it's for the long haul. Gloves will also be a necessity (walmart, autostore, etc.)
Good luck, I hope I put forth some useful ideas and such, and post some images when you've got a product