One word:
plastics
guitar.
I actually take my Ibanez archtop into bed with me many nights and fall asleep practicing fingerstyle patterns. Yes, that means making room for one's mate du jour in one's bed, but it depends on whom you're with.
I never crushed the guitar accidentally, and I never heard complaints about snoring. Which are specious complaints, without a doubt.
Can one do it with a keyboard instrument?
Yes, of course. But, in that case it's more a mental exercise in composition, ear-training, and so on.
Since that's the case, I propose, the "keytar."