I wasn't sure whether the latter firms had found some new pixie dust by now. Good to know. Obie Fernandez has a talk online somewhere about billing where he says something like no one working in Rails should bill less than $150/hour and that he bills himself and his developers at $250 but will occasionally give discounts for various reasons. Maybe I have numbers wrong - just found it - http://www.infoq.com/presentations/fernandez-sales-do-the-hu...
I recommend watching it. Good talk. Takeaway point - always err on the side of charging too much :)
It seems to me most Rails jobs are either for companies who chose Ruby because they really know their stuff, which is great, or companies who chose Rails because 2 years ago it was touted as some sort of Web app pixie dust in Wired Magazine, which is often less fun :)