http://www.urethanesupply.com/Other-Fillers-1/Padded-Dash-Filler/
I used this and its very flexible. I can push in on the repair sections 1/8" or so and it doesn't crack. The only problem I had was it looked perfect after I did it. A few days later I thought I would spray some SEM vinyl paint on the whole dash just to give it extra UV protection. I had read on another forum to prime it first if you did that, but I didn't. it made the repaired areas swell up about 1/8".