Options for hub gears on a 120mm dropout?

I'm thinking about getting a singlespeed frame, but as I live in the Peak District a few gears would be useful

Are there any 120mm geared hubs available?

You can certainly get Sturmey 3 speeds that will fit.
I'd go for the newer SRF-3, which is a superb piece of kit, rather than the old (and ubiquitous) AW3.
If it is steel you can stretch it out to 126-130, and then you can fit something with more gears.

You can also get 5 speed Sturmey hubs in 120mm

Thanks

can anyone point me in the right direction where to buy these hubs?

I think I'd be looking for a deep v 36 hole rim in orange too as it seems all Sturmey hubs are 36 hole

SJS cycles are pretty good at that sort of thing.

You would struggle to get a usable range out of a hub gear (affordable ones) for somewhere like the peak district, you really would have much more fun with a conventional derailieur setup.

If you want the simplicity, just go for the single speed. Should be fine for little jaunts. Hub gears and finickety. They add drag, weight, and a feel of disconnected innefficiency to empty spots where nothing engages.

It will be a pootling bike, but there are hills everywhere

The other option was to get a genesis day one alfine, but I want something more classic looking

I've got a 27" alloy wheel with a Pelissier QR hub that is 121mm and takes a 5 speed as standard.
In fact any hub can be built up to be 120mm, you just need the right axle and correct amount of spacers/locknut.
Even a longer axle like a 126mm can be re-adjusted with the removal of spacers & be trimmed down to fit without worrying about redishing.

You can't always swap axles on hub gears - they often have parts that are pressed onto the axle, or keyways machined into them - so if there's only one length of axle made for them, then that's the only axle you can use.

An AW or SRF3 (the massively improved modern equivalent) will give a reasonable gear range. I had mine set up to give (from memory) 35", 50" and 67" which was fine for the 10% hills in the Purbecks (I didn't ever need to get out of the saddle). 50" was direct drive and no less efficient than a singlespeed.