Sacha White (Vanilla) builds some gorgeous bikes! From what I've seen he can do pretty much anything you want with steel using any construction method you like (lugged, fillet brazing, TIG). I don't think their prices are that high at all for custom frames. I have a custom steel MTB frame that was built for me by Carl Strong (www.strongframes.com) and it was around $1200. Someone here on this thread said that Vanilla is getting $1500, which is quite reasonable (super reasonable if that's for a lugged frame).

All that being said I own two production Rivendells, an Atlantis and a Quickbeam. Both are excellent bikes and are very well built. I'm completely sold on Rivendell's fit and riding philosophy. I guess you could say I'm a Rivendell devotee. So I definitely recommend taking a strong look at Rivedell too.

I guess what I'm saying is that you really can't go wrong here. If you choose one of those two you're going to get a great bike. Take your time and pick the one you think is right for you. Good Luck!