Which companies perform the epilogue and which don't? The epilogue being Solor and Gamzatti's wedding day and as soon as they say "I do", there is a great storm and everyone is killed (including Solor) and Nikiya and Solor are once again united in the kingdom of the shades.

The Epilogue you mention is really (as far as I know) Act IV of the original production. The Royal Ballet includes Makarova's imagining of it, and I believe the Kirov's reconstruction of La Bayadère includes the original Act IV.

I just finished watching a video of Paris Opera's Nureyev staging (the video is of the premiere, I think), and there is no Act IV. I thought I had missed something!

No, in the original Act IV I believe is the shades. This is another good topic, I will post it now.

Minkus Pugni, you really must get hold of some literature based on sources and read it. Hans is quite right, Shades was originally Act III Scene 5. Act IV is Scene 7 and subtitled "The god's wrath." The ballet concludes with an apotheosis.