An alternative is to make large cardboard cutouts, like the movie Home Alone, but replace the bad guys with high end LG steam washer and dryer. Have another set of cardboard cutouts resembling the typical buyer in your building. Maybe throw some real dirty laundry in there to step up the realism.
I am extremely creative and I always try to point out the positives and give my buyer clients ideas for what they could do, but 99% of the time they tell me its too overwhelming for them.
For this same reason it is really important that your home shows well. It is hard for people to see past different decorating styles than their own and to fix any minor eye sores, no matter how little they seem to be to you.
Most buyers don't want to do work on a new place, they just want to buy and move in. Every buyer has different priorities, wants and needs. If in unit washer/dryer is important, they will not be looking at your condo. Most buyers don't even want to do easy things like new carpet or counter tops.
Best of luck,
If you're going to try to tout that the building allows in-unit washer/dryer, I've found that buyers just don't have enough imagination, nor do they have the desire to take on a project like that. In my opinion, it would be a better selling point if you already had the washer/dryer installed.
Now... that being said... will you get your money back?? No, probably not ... but it will make your unit more attractive, and possibly easier to sell.