I spoke to Ben Cooper (Kinetics) last Friday and it looks as though a Schlumpf High Speed Drive will give me exactly what I want... a low 30” the standard 56”/74” and a higher 90” top gear.
These are some odd calculations.. the Speed Drive is a 1.65/1 overdrive 2spd hub.. the High Speed Drive is a 2.5/1 overdrive hub.. if you geared your bike for a low of 30", then your 'standard' would be a 30"/48" when in direct drive.. if you have a Speed Drive, when engaged in overdrive, you would have 49.5/79.2 .. if you have a High Speed Drive engaged in overdrive, you would have 75" and 120"..
Speed Drive ratios would basically overlap at 48" .. 30"/48"/49.5"/79" .. so basically a wide range 263% 3spd
High Speed Drive (no overlap) 30"/48"/75"/120" .. here you have a true 4spd with 400% range ..