Are there any lockers available to stash a carry-on for 5 or 6 hours? I'll be arriving and departing from Terminal 1 (UA).

According to

http://www.changi.airport.com.sg/changi/facilities/services.html#1

there are lockers in the transit lounge (before immigration and customs), but are only available between 7am and 10:30pm. So that won't be useful for the UA SIN mileage runners.

Has anyone used the 24 hour luggage facilities in the basement level in Terminal 1 West (after immigration and customs)?