The only problem with rearing the smaller breeds of pigs, is that unfortunately they cost the same amount as their larger bretheren to slaughter and butcher.
Our abattoir charges the same price for slaughter for most pigs - £18 odds, if they're so big that they have to go through the cattle lines (to stop them trailing on the floor once hung) then we pay a higher fee but that's mainly for cull sows.
All the butchers we use work on a price per kilo for butchery so it doesn't work out any more expensive having a smaller pig cut - but generally by 10-12 months our Kunekunes are around 80-85Kg live weight anyway.