8 XXX : bdsm

Engineer here: I'm not sure which fittings you use, but the flexing the frame will do during any form of suspension might eventually cause the pipe ends to work themselves out of the fittings. This is especially the case of you put loads in the middle of the the pipes. Make sure to use a fitting locking agent such as loc-tite. Alternatively you can still a hole through each end/fitting and place a tight fitting locking pin through the hole. If you think the pipes flex too much, add some braces. Other than that; nice rig! I made my bed from truss beams. Have fun!
Best four poster bed I've ever seen.
Envy!