| Tim, the easiest way is as you say to get hold of a write off with minimun damage to the frame.
If your trying to do it from just parts, it still cost a fair bit as you will need to get hold of all the following bits, and a few other minor bits
Frame
Headstock
Yokes
forks/spindle
Wheels/discs/callipers
mastercylinders/hoses
Bars/throttle
tacho
Swingarm/hub/rear brake
Shock/linkage
subframe
ECU/Harness/coils
Tank/pump
Fairing/bracket/seat unit
Engine/injectors
radiator/oil cooler
foot rests/gear change
Chain/sprockets
battery/reg-rec/solinoid
Exhaust
start pricing up the bits, allowing for your choice of part, such as Ohlins shock, sps engine, Brembo radial master cylinders or what ever and then you could always add in a slipper clutch, quick change sprocket carrier etc.
or expect to pay around £3k for something like my 916 Strada race bike, without things like the 54mm exhaust, or mag wheels etc | 
skidlids
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