That cute little Kitfox seems to go well and sounds nice with its 65hp Rotax 582 2 stroke...brand new engine should be well under 5k,
Yes it will burn around 18 LPH but how much fuel can you buy with the 11K plus saving over a 4 stroke Rotax,
Bet you can buy many s/h ready made a/c though for less than the kit price,
Are you sure you want to build it yourself....I think the Skyranger range are quite competitive kits see Flylight Northampton...cheaper with the 4 stroke Jab engine,
http://www.flylight.co.uk/tuition/home.htm