I have a Windsor 5-string, which has 6 machine heads - the 5th string emerging at the 5th fret through a tunnel.

I also have a Matthews 7-string banjo, which I bought for £30 at an `antiques' (ie assorted junk) auction a few years ago. It was in a bit of a state but it is now in a playable condition. I currently have it tuned the same as guitar open-G (DGDGBD), following advice on the subject from Ivor Mairants. But I'm sure there must be other options. I'd also be interested in what strings/guages people might recommend for it as the advice I got suggested I should use only the lightest guages to stop it `folding up' under string tension. That does make it quite difficult to play as the strongs are very easy to pull out of tune.