On a daily basis, I would not worry about it. If your concern is during parties or with special guests, you could try draping the machines with cloth. Use a table cloth or pretty fabric, even a pretty flat sheet will work. Unplug the machines first if that worries you. After draping the fabric over them, you could always set a bowl of flowers on the dryer, or some other decoration. Most people will probably not look hard enough to realize there are machines under the fabric, they will probably just assume it is a cabinet. Make sure the fabric does not hang onto the floor, you don't want anyone to trip. If you don't think it will stay put, just use some masking tape in spots that don't show to secure it. I used to do this with a particularly ugly cart in my kitchen, luckily I found something better to replace it. All anyone ever said about the draped cloth was, "oh what a pretty table cloth, where did you get it?".

Why not conceal them behind a false cabinet front? The dryer could actually be built into a cabinet with a counter on top and a bi-fold door in front. The top-loading washer might be a little trickier but you could have a special counter made that is on a pneumatic hinge that lifts up(sort of like a toy chest lid) when you need to do laundry but otherwise acts as a countertop. I suppose if you're only concerned with parties and such, you could build a cabinet surround for the washer with brackets on the top to place a removeable "counter" when you have guests over but otherwise store it off to the side. This might get in the way less than a counter that you have to lift up each time you want to load the washer. Have you thought of switching to a front-load washer which could then be concealed easily in a cabinet like the dryer? I've been in a kitchen where I didn't even know there was a washer and dryer because they were built into the cabinets- but they were both front-loading.

The other option- can you put up sliding or bifold doors to closet the whole thing in? Or else!! get one of those hospital curtain type tracks and hang a lovely curtain across the whole thing. This way you can simply slide it off to the side when you want to do laundry but could otherwise select a very pretty curtain to hide it away.

Amy
Fremont, CA