In Slovenia, Planica nordic centre:Techincally you can, but its not usual. Kolobnev's hotel near Valencia where Remco and Van der Poel often go is the only one that I know of, though there may be more.
ten rooms (20 beds) in the Dom Planica hotel (up to 6000 meters above sea level), test facilities (up to 6000 meters above sea level) and sports halls (up to 2500 meters above sea level).