I'd also vote for the mandola. A friend of ours had an industrial accident which makes guitar playing a non runner, but does a fine job - he used to play in a duo, one half playing the mandola in an open G and the other mandolin type tuning and it worked really well.

My other half plays one of these and it's a really nice instrument.

freshwater mandola

We call it Nelson (Nelson Mandola) - gerrit?