I think that can be done.
We're four developers in our company,
but starting at least seven or eight sites a year.
Most times a project is handled by a single
programmer, but each of us has his strengths, of course.
It's a great help if you have somebody around with
really good knowledge of HTML/CSS/JS.
So the amount of work can be handled, maybe
you should consider to use the help of a really good
hosting company with some experience in RoR, since that
would take off a large burden learning and finding
information on installing and running your app. I'm
always happy, if I can concentrate on programming
instead of maintenance and installation.