I have the new iPad 2 with the smart cover and when I saw the fridge magnet demo my mind for thinking of how this could be utilised.
I took a cheap magnetic whiteboard 99p from the local market, cut it up to suit the top box on my car dash, covered it with black felt (pressed thinner) and spray mounted the felt to the metal.
Then using automotive tape fastened the unit to the top box and voila.
Total cost £2.30
Hope it inspires you.
p.s. the install is for satnav only. Seems I can't add photos till I have 3 posts