Every time that I think of a home-made hammock stand, I think of a modified tripod. I haven't stumbled across anything that looks like the image in my head, though.
The stand made by headchange4u seems like it would be unstable on unlevel ground.
I haven't made any sort of hammock stand yet, and this is purely speculation on my part, but here's my idea.
The picture here might do a better job of explaining my idea than I could ever do by describing it. However, I will try anyway.
Materials for one support (total of two needed)
the correct length of 4x4's. (To make a 3' tall support, this would be 11' 6".)
2 heavy hinges and the bolts to attach them.
2x4, about 4', cut into 2' strips.
4 screws to attach the 2x4's
1 eye bolt
Directions to make a 3' tall support.
Cut a 3' section of 4x4 post. This is the main upright for the stand.
At the very top, on two adjoining sides, attach the hinges. They should close flush against the 4x4 upright.
Two more sections of 4x4 will be needed, each 4' 3" long. These are the diagonal supports. In order for them to sit flush along the ground, it would be best to cut one end at a 45 degree angle.
These 4' 3" sections should be attached to the hinges, with the 45 degree aligned so that it will sit flush on the ground when opened.
A locking system will be needed to ensure that the legs stay open. Such a device will be simple to implement. For ease of description, the two 2x4s will need to be attached to the upright post with screws, loose enough so that they will spin. Attach the other screw to the diagonal support, leaving it protruding enough to "catch" a 2x4. Notch the 2x4 so that it catches on the protruding screw, locking the support in place.
Finally, an I-bolt needs to be screwed into the main upright, directly on the edge of a corner, in between the diagonal supports. This is where the hammock itself is attached.
In the image, a few more cuts have been made on the supports to make them look better when opened. Without an extra 45 degree cut made at the top, the square top of the diagonal support would make an angle with the main support.
When folded up, it will appear that three 4x4 sections (of two different lengths) are stacked in an "L" shape.
Hope this makes some sort of sense. Is there a reason this wouldn't work? Or would it just not be worth the trouble. Obviously, two of these would be needed (unless a tree or something else was used). I think that using the modified tripod would allow one to use these stands on some fairly uneven ground. Also, there is no hardware to set up (like attaching the two pieces of the stand together, as in HC4U's example), so I think it is a just a bit simpler, in that regard.