I might end up going to Ikea in the end... okay. That's just an excuse to go to Ikea. I love that place :D I'm going to give this a go first since I already had it.
I'm going to give it a try today and see how it goes before we do anything else with it.

I love ikea too. Any excuse to go :)

Don't be discouraged - it looks like an awesome sewing table and you are almost there! Your earlier thought about the 2x2s plus the cushioning may be the perfect solution in the long run. Glad to hear that it's workable now.

Thanks so much :) I am going to call my father in law in a bit to let him know what I've done and the suggestions that were made. He was probably up half the night trying to brainstorm. I dreamt I was trying to escape from some weird installation full of aliens and aliens that look like humans. *shudder* I wasn't even watching sci fi before going to bed lol.

I have a different floor mat that I'm going to try. Something will happen. There has to be a perfect combination somewhere :D

Yours looks really good. Sorry about the vibration.

My machine is heavy and has suction cups on the bottom, so the vibration is minimal. My Singer longarm has a kind of exposed frame on the bottom, so when it was vibrating, we simply screwed picture clamps onto the carriage and bolted the machine down. I'm not sure how you'd bolt or clamp it down with a DSM, though.

"now that this one has a hole in it... it isn't exactly a usable surface for anything else so it will most likely have to get chucked"

You could always make the hole bigger, get a piece of clear plexi to cover the hole, and voila! you have a light table.

How about covering the hole by adding a new top to the desk for a cutting station or a really oversize ironing area?

i think if you got a piece of wood as thick as the space is between bottom of the top and the top of the bottom shelf{where the machine is ] and 4 carriage bolts ...you will have a small bump but out from the machine where the bolt is [they have rounded heads your fabric should not get caught on them ] and maybe one in the back of machine ....can't see how much room is there ......but that would make the shelf solid and not vibrate so much ...good luck

Look in the carpet/throw rug section of Walmart, or which ever big box store you have, for a closed cell foam floor mat. They are like camping mats or exercise mats - which you could also use but you won't have as much waste with the floor mat. The floor mats are 1/4 inch thick and have pretty designs printed on them. I use one under my embroidery machine. I can embroider in the morning before anyone is awake, with no complaints about noise. Cut it to size.