All of the above!
If you want cheap hour building buy a share in a 150/2 where the other owners are happy for you to do that or block hire a similar aeroplane. Deals can be had, look in the small ads in the mags for these.
Alternatively go to the States and do a deal with someone who has a an aeroplane for such an undertaking. NOt only will it be a lot cheaper to go over there as far as aeroplane and fuel are concerned. If you consider the money saved in landing/handling fees and the vast amount of fun you can have in GA in the States it is clear that for something like hourbuilding the US is the place to go.
Just back from a short break there myself. For Flying it is truly the land of milk and honey.