After fooling around with Photoshop-generated backgrounds, I decided it took less time to make a colorful collage and scan it than it did to mess around in Photoshop trying to make one part of the background look like painted lace, another like torn paper, etc. I made a couple of quick and dirty collages using spray adhesive and my copious collection of paper and fabric scraps.
This is a snapshot I took in New England, of a deserted house under bare trees.
Next I applied the Stamp filter to get a strong black and white image.
I cropped the picture so that the large tree on the right was the dominant image, overlaid it on the pink collage using Multiply blending mode, and cropped again.
I like the subtle, mystical effect of the overlay blending mode here - the door seems to be floating in space. Cutting away the image on either side of the door and inserting a contrasting layer made the floating effect even stronger. This cut's not perfect, but good enough for experimental purposes; if I decide to print this one onto fabric, I'll select the sides very carefully before doing anything else, and try out filling them with different colors and textures. I'm thinking a dark, cloudy sky might look good here.
And finally, here's a snapshot of a jali in Udaipur, layered in Multiply mode over two layers of the yellow collage (one rotated 180 degreea) and the top collage blended in Difference mode.
Nothing so great here, but with a bit more fooling around I think I might come up with something that would be interesting to print on fabric and then to embroider/bead/quilt.