I have heard of problems w/ Rimadyl as well. But I do know people have used it here w/ success. Like LadyMom said though, it can be scary. There are risks w/ any medication of course, but pain meds will always have add'l risks. Is your vet still open, can you call for consult yet tonight? How is DaVinci's pain?
Here was a link w/in the page you gave, which was also helpful:
The Senior Dogs Project