Mine did the same thing when I took off the original....just snapped into pieces. After my repaint, I found this 1/4" stick-on chrome that works well. Stuff is cheap and seems to hold up well. I think it was $15 for 20ft or something like that. Did the tank, the seat (sticks fine to my aftermarket vinyl seat cover) and then had enough to do the tank again when it was repainted a second time (long story). While it doesn't cover the tank edge (i.e. wrap around the edge), it fills the space around the bottom and front perfectly and is very flexible. Like someone mentioned above, you might be able to find that auto door edge stuff that's wide enough to work as well. Same idea.
I think I found this at Meijer or Walmart. Probably at the auto parts store as well.