Most folks consider the jointer bed length the determining factor on
what can be reasonably jointed. I think you can easily go to about
twice the total jointer bed length with the board and still get
reliable results with good technique.

Rollers "might" help with longer pieces but they will introduce some
problems with accuracy. They may be less of a problem with face
jointing, than they would be with edge jointing. Regardless, I'd avoid
them.

In addition, I would say you should joint the material at the shortest
size that will work for the project (Unless it's really short). Just do
the rough cross cuts early, then do the jointing. Only joint a long
unweildy piece if that's whats needed for the project. Of course this
is all just opinion.