The washing machine's plumbing and drain, when/if they fail, will be a huge problem for moisture, but you are also creating a venting conundrum by running appliances that need dedicated external venting, which also tend to be sources of high off-heating, in an area that is normally highly HVAC regulated.
Then there is however you run your dryer; building code doesn't allow any gas-powered appliance in a sleeping quarter (I believe), unless it is well vented. A purely electric dryer would work, but we're back at the venting vs HVAC issue.

But go for it. I've seen some weird things touring homes that fly in the face of all conventional thinking but were 100% driven by some homeowner's personal vision of functionality (fully exposed shower in a full bathroom, for example...shit and shower at once).