Airframe weight?
Go to the "list your setup" thread in this forum and find all of the 40-50 ounce planes. Figure that the average of those is a good starting point.
OR, go to the Brodak's site and get an electric setup for a Cardinal or an Oriental -- that should be pretty close.
Banshees need their nose shortened for IC because they were designed for a Fox 35 with a tongue muffler (or no muffler at all). That's about the lightest combination that'll power one, so if you use anything heavier, or even if you use a Fox 35 with a muffler, the thing comes out horribly nose heavy.
An electric, on the other hand, distributes the power system weight over a longer chunk of space, so your Banshee isn't necessarily going to be nose-heavy with all the electric "junk". Moreover, many profiles designed for electric don't have long enough noses to fit all the stuff. Buy the parts, mock them up on the nose, check the balance, and then decide if you want to whack the nose shorter.