Stackable Washer / Dryer Upstairs

I think samsung has a self leveling machine that doesnt shake as much.

I would say put some plywood down and put some peel and stick tile on the plywood so it doesnt look so bad. Dryers arent all that heavy so its not going to put much more weight on that spot. Put something level and hardy under the washer and you shouldnt have much of a problem. Front load washers have shocks (some more than others) and dont tend to shake as much as a top load washer would. I know that my duet has four shocks and it works to level itself if its not level it stops tosses the clothes more and starts again in a spin and even in the high speed spin it doesnt shake as much as my top loader did.