I am starting up a swap in the Scrap With V forum. Have a read and see what you think.
The stamped image can be any stamp you may have in your stash, for eg journalling spots, flowers, or any stamped image. To enable the recipients to colour the images any way they want, if at all possible, emboss the stamped images you make. This will allow the recipient to colour the image without the risk of the ink running. Also please stamp your images onto white cardstock.
So, you send enough stamped images for everyone participating in the swap, if possible, you emboss your images, you stamp onto white cardstock, and ensure your images fit into a standard sized envelope.
If you are keen to join in, please head over to the Scrap With V forum.