Not sure if I’m in the correct place of posting this i apologize. I have a customer on Fripp island South Carolina that wanted a 14ft bunk bed. Originally they gave me a photo found online asked if I could do it. So i told them I could but the original room would of been ideal but they moved it upstairs which really made the design aspect very different layout things needing moved and supporting a factor due to placement in room and not having walls to anchor with. So we spoke on doing bookshelf’s as bases for this double twin mattress bunk bed which will have a queen underneath it running opposite direction. They’ve now decided they don’t like the book shelf because there same width as the bed which i told them I could rebuild the book shelf since iv only done the sides and shelf’s and now was the time to decide especially Since they need it done by this Saturday right before Easter! So they asked if I could suspend it from ceiling and not with chains that want me to figure out how to suspend with steel tube and case it out. So my question is how to figure out the size and anchoring factors to recieve the highest possible load i can achieve out of it. The bed is anchor to 12 studs with 4" timberlocks 2x4 joist are hung with hangers and bed is wrapped with 1/2" birch plywood, corners have simpson brackets to help keep movement side to side down and everything is screwed tight. So i need some help if anyone has Any suggestion please it would be much appreciated! I know I’m not from dallas but I’d love to figure this out for them and be able to add to my portfolio for this island because 2000 homeowners want custom constantly and I’m slowly making my way to be the most valuable contractor on the island! 
So everything is wrapped and I am doing ship lap underneath. So this thing will look amazing if i can give them exactly what they want. Bookshelf is not even close to be finished so please don’t trash my work til it’s completed everything has steps to it before it finished and there is still much trim out bondo and painting to be done
Questions.
Can you weld?
Do you have the equipment?
Can you penetrate the ceiling?
Are the ceiling studs in an appropriate place to meet your suspended piece?
Is cost an issue?
Do they expect you to paint the steel?
What kind of tube? Square or round?
Love the needed info! Glad to have you reply back. So i personally don’t have equipment to weld but I can weld just never done it for something like this. So I’d prefer to have a shop or a buddy do it. Cost isn’t a factor what so ever. Ceiling is to second story but yes i can penetrate and planned to do so for anchoring and finishing drywall once installed. Not sure yet of floor joist above until in the morning when i cut open a section to find out so i can move forward or figure something else out.
My idea were maybe use square 1/4 thick and if joist are in my favor attach using some kind of carriage bolt through square tube and joist with washers to hold it tight without damaging the tubes structure by over tightening or sandwiching between joist an 2x4 with carriage bolts
Then it would end up encasing the tube with birch so it appears to be wood.
There isn’t much side to side.movement so I’m not concerned with bed shifting. Just wanna make sure I can have bed supported and if some grown man decides he wants to sleep up there or two grown adults that i have the structural weight capacity at it’s max. I’d like to be able to support 1000 pounds of.more between two steel rods of some kind.
Not a fan of the carriage bolt idea. Weld plate to one side of tube, drill hole, put plate backer on the back. Put bolt head facing out if not covering. Like 3 tubes better than 2.
Just my 2 cents.
Look to the aesthetic first. That will define the position and size of the cosmetic aspect.
Construct the framing support in the ceiling as needed.
Use saddles on the woodwork and connect with all thread.
Add woodwork to taste.
No welding.