I use the Z2 auto mini CPAP and the lightest nasal pillow mask I could find, the airfit p10.I have sleep apnea and require a machine nightly. I bought a travel machine, cigarette plug adapter, and a battery pack with a cigarette outlet. The CPAP setup I have can get me 5 full night's of sleep (~35 hours) plus 5 days of cell phone charging with one battery pack and it comes in at about 5.5 pounds. The battery is the heavy part of that setup. All in, it was ~$700 out of pocket for the setup. Insurance doesn't cover a 2nd machine...
You might also look into the custom fitted mouth guards. They've proven effective for some patients and would be significantly lighter/smaller and of course no worry about power.
That's the battery unit I have. I bought a 12v adapter made by my CPAP manufacturer to connect them.
I have a slip on bug net from hammock gear. It has a stuff sack made out of bug netting. It happens to be the perfect size to put my CPAP and battery in. I then hang that from the hammock hardware on the head end. This put it about a foot above my head.
i have a mesh hammock organizer on my structural Ridgeline that I stuff the mask and hose in until I'm ready to use it.