Remembering when I was in similar position back in the day I bought one KH26 and in less than 2 upgraded :
pedals
seat post
seat
seat post clamp
tire
crank, brake and frame
then mount a new wheel in order to remount the discarded parts (except saddle and pedal that I dislike and ardent tire that is not strong enough for my weight) and leave this backup muni in my parent house in order to avoid muddy muni carriage then I visiting my parents.
Buy the way I bought one 24" to in the same time…
At your place I would go for :
24" Nimbus MUni - Black
+Magura HS33 Brake - Black, 2011
+Magura Brake Clamps
==========>or better HS33 2014 )
+Nimbus ‘Flat’ Unicycle Saddle - Black (ask you seller if it’s possible to upgrade the saddle for less…).
Even if you have to buy 2 saddle it will still cost less than one brakeless KH !
An other fantastic improvement will be to buy one Schwalbe Big Betty.
I begun muni with a lent 24" duro what make me choose to purchase a 26" with an other tire" !
Big Betty is far lighter, roll better, clean mud faster, better on wet rocks… I use one in 24" and one in 26" !
Marked 2.4" in spite of marked 3" for the duro but look at the real 
measurements :
source tartybikes 