Anyone build mats like he describes here?
He suggests 1 inch of foam, but most places I know of use at least 1.5 inch mats. Is 1 inch sufficient? (that's what she said)
4later 
depends on what you consider "sufficient".
1 inch mats are sufficient for rolling on the ground. so are puzzle mats.
i would hate to roll on that but it's "sufficient".
I think moe, importantly is what is underneath the mats.
1 inch is fine if you're rolling on carpet, but terrible for concrete. 
It's more than enough. I trained at the old Gracie academy and the mats were great. He is using 1/2 inch carpet padding and 1 inch of the poly foam plus the carpet.
If its good enough for the gracie academy...
If you are worried about the 1 inch foam, just get a thicker one. Cost more but it's more padding. Pretty cool that the whole top just velcros off and they can walk all over the padded carpet with shoes. Depending on what kind of set up you needed for the given moment you can roll up part of the vinyl and have people walking on the uncovered part.
Sub
Our academy is expanding and we're matting the new space (we will now have two training floors) this way tomorrow morning.
I think we're doing 1.5 inch foam with the vinyl. I'll update with pics tomorrow.
We followed the formula pretty much exactly as it is explained in the video and it worked great, not too firm and not too soft. The carpet padding is key.
I'm very happy with the results, it's much cheaper than getting standard mats and they're excellent.
That was awesome
Depends on what type of foam you are using. There are many different densities and types.
1" thick of 2lbs low density closed cell foam with a good carpet padding under it will work great.
We did carpet padding, then 1" of the low density foam described above, then actual carpet, and the vinyl on top with the velcro adhesive on the edges.
It turned out pretty nice. Personally, I'm not a big fan of the ripples in the vinyl, as it's impossible to make it super-smooth, you're always going to have a bit of give and play.
The other training floor of ours is Zebra mats wall to wall now, so I'll be hanging out over there :)
I looked into this method and it didn't seem very cost effective. I could have gotten flex rolls for the cost of the padding alone. Add in the carpet pad, vinyl cover, and labor... didn't seem worth it to me.