If anyone is building a PVC fence, I wanted to point out of a source for finials.
I purchased the plastic finials pictured below from DecorativeIron.com. The item number is 16.2029.
These square finials will fit over 1/2" schedule 40 PVC. However, it is a very tight fit and it would be very difficult to get them on without heating up the PVC. If you use a heat gun to warm the PVC, the finials slide on very quick and easy. It creates a very good fit after the PVC hardens. In fact, it's very difficult to get them off.
Shipping was a bit high from DecorativeIron to Virginia at $14.53 for 100 finials, keep that in mind if you order.
BUT... they look pretty good and they kept Bucky inside the graveyard.