It is possible to have several panels and place them on different screens.
All panels share one config file.
Expanding of a panel across several screens can be problematic since there is no guarantee screens are aligned (and most probably they are not).
As you may know, Razor-qt is merging with LXDE, so there will be no any new features added in Razor-qt, only critical bug fixes which by the way goes terribly slow now.