I want one of
these 29-inch-wheeled mountain unicycles:
I can't go fast enough on
my current 24-inch unicycle:...which I have had since I started learning in March, and which I now use to commute to work (a lot of fun) - it's capable only of a moderate jogging pace, limited by how fast you can pedal without wobbling.
Also the thin road tyre is not so great on uneven ground. The 29-er should be about 20% faster and make it easier to ride over bumps. It also has much better, grippier pedals.
I'm half considering
this speedy 36-inch monster:...which would be 50% faster than my 24-inch, and is
quite capable of some offroad riding too. However, it's a much bigger step up in pedalling 'gearing', so I'm worried that I might not be able to get up the Wellington hills at first, or ride slowly enough to cope with pedestrians on the way to work.
Probably I will go for a 29er for now, until I'm a bit more experienced.