Finally,
After doing this two times unsuccessfully in under two hours, I was able to get the things like Render Settings and workflow considerations behind me and produce something that I can really be proud of. My textures are large, 2048x2048, but I did not see any stipulations about that. I suppose if needed I could scale them down if it meant not getting DQ'd from the competition.
You can download (hopefully it isn't too big) my texture sheet
here
I wanted to create a look that was representative of an oak like texture that has some bright, but subtlety presented colors that would suggest a poisonous plant. I developed this pattern with use of some filters (palette knife, poster edges, maybe sponge). I tried to create some depth between the resulting patterns by using selecting a color, taking it onto another layer, and using inner or outer shadow.
Once I was happy with this pattern, I scaled it down to 1/4 of the canvas size and copied it into every quadrant. I was lucky in that I didn't have to worry about seamless textures because the algorithm photoshop uses for these filters is seamless. I think I repeated the scale down process once more. The result is I ended up with a pattern that's small and repeatable so that I can give a lot of fidelity at a close up level to the final texture.
I then took the pattern and scaled it into a different 512x512 document. I created another layer on top of that and masked it out with black. I used a circular gradient to unmask the middle (dragging outward) and ended up with.... a zbrush alpha that resembles my base diffuse texture!
Zbrush was pretty much using that alpha (far away camera and low intensity produced the best results). I then went back in and lightly snaked some vine like topology around the plant. I finished it up with a closer and smaller drag dot along the snake like vine to make sure it didn't look too fake. I also went around the plant and bubbled out the edges that surround the thorns themselves, almost like a knot on a tree. I baked out the normal map from Zbrush using the Maya best quality settings, and exported out the highest levels in obj.
I then used xNormal, my new best friend, and baked an AO using the high obj. This took a little over 30 minutes alone with higher sample settings and 2048 resolution.
The next portion I worked on was back in Photoshop. I took the AO and the Normal map and used them to get a very feature rich diffuse map. I think it produces something that you can see from a distance, but when you get close you get some great details. I also made, as you can see on the texture sheet, very simple thorns.
The rest of my time was spent tweaking lights and a few settings for a good render, taking the resulting shots into photoshop and compositing them at the speed of light.
I'd love to hear comments and critques.