I think a significant part of the cost when using a container is the engineering work of removing/packing and replacing the wings. The simpler the aircraft, the easier this is likely to be.
Also, costs to consider are - the US aircraft probably doesn't have FM immune avionics, the altimeter is inches, IFR machines are likely not to have DME or ADF (because they use the GPS). If you are going to place it on the G-Reg, there may be SB's or manufacturer recommened service items that have not been completed - as these are optional for aircraft not used for public transport in the US.
I did it and enjoyed the vast majority of the experience and have the aircraft I wanted, but it didn't work out that much cheaper than a roughly compatable European aircraft. The key for me was choice - about 200 in the US which broadly met my requirements vs. 3 in Europe.
The 'Danish Thing' works, but if you are organising your own Ferry Pilot make sure you, the agent, and the pilot are crystal clear about the route your are flying and the process. UK Customs objects to the concept and will be checking that the process has been done correctly when you fly in from Denmark.