I like your siolution of displaying hours 1-6 and then 7-12 with minutes inbetween.
Another solution might be to have a "rest" position on the left and then hours 1-12 and minutes 1-60 shown as concentric scales. The needle could start off in the "rest" position -- then move to indicate the hour -- then move to indicate the minute -- then return to the rest position...
@HeyJoe: ...On my next iteration Im going to use a linear scale and apply a nonlinear correction factor on my output value.
That's something I might be doing -- alternatively, for some ptojects I might want a non-linear scale that doesn;t match the non-linerarity of the meter. In thsi case I might use a look-up table approach and then interpolate between table values.