In this video I make an 35 kg (80 lbs) anvil from railroad track and some pieces of mild steel. I made the horn from two pieces of railroad track welded together as well as the hardie hole. I'm planning to add on a square horn on the other end in near future. I didn't film the rebound but I can assure you that it works great as you'll see from future projects made on it.
If you're planning on doing a project like this yourself be prepared for a lot of angle grinder cutting and shaping. It's pretty tiring and your hands may hurt the next day. If you have a torch or a plasma cutter this will be much easier. Also be prepared for a lot of welding and I burned probably 3kg of 7018 welding rod on this.
I've made this anvil about a year ago and it is working and holding great. I've already made quite a few projects on it and some of them were some heavy forgings which I'll upload soon. I'm trying to
edit as much footage that I've filmed over the course of this year now that the school is over.
I would also suggest you watch this great video by Paul Krzyszkowski if you want to make your own anvil: