So i actually just finished my non tree setup this morning. I copied the tensa solo idea and made a single/double hang setup for one or two hammocks off the back of the canoe rack i built for my truck. As far as the connection for two poles: There are multiple options here.
1. Lashing- you can tie the tops together in a crossed fashion just like a teepee/shooting sticks. (Look up cheap diy shooting sticks for examples)
2. Use a long bolt and wing nut. You will have to drill through holes in the ends of the poles, and use a bolt that is approximately 1" longer than the width(diameter) of the two poles. Attach your anchor line in between the poles on the bolt. I only recommend this if you are using metal poles.
3. Do a tripod and then the anchor line isn't needed. Look at the eno hammock stands for ideas.
4. Scavenge the top piece off of an old swingset and modify accordingly.
5. Buy a tensa 4. And go camping. Lol

Unfortunately, i do not have a disposable income so I make alot of the gear I use by copying designs I see, and then making my own version with scrap i find lying around. Sometimes, though, buying the good stuff is way better than anything I can make myself. It all depends on you and your level of construction skills. Hope this helps, let me know if you have anymore questions. ��