I have stamped a lot on fabric and walls.
First, I have a lot of wall stamping in my gallery:
JojoBallard's Gallery at Splitcoaststampers
I think they are mostly on page 3, and maybe a few on page 2.
When stamping on walls, the easiest thing is to use the acrylic craft paints like Delta Ceramcoat or similar paint. There is no need to seal the stamping or do anything special. When we moved out of a house I had stamped in, we painted the walls for renters. It only took one coat of primer and one coat of white paint to cover even really dark colors. SU didn't recommend stamping on walls with Craft Pads because they're really hard to paint over later because they are not water based.
For fabric, I would recommend using acrylic craft paints mixed with textile medium. You can buy the TM at any craft store. I have purchased it at Michaels. The bottle will tell you what ratio to mix the paint and TM.
The advantages to paint/TM on fabric is that the stamping does not peel or crack like it would if you used straight paint. The advantage over SU Craft Pads is that it will not fade with repeated washings. Also, you can get unlimited colors. If you have any further questions, feel free to PM.
HTH
Heidi