Seb,
You may be aware that the FAA websit shows 4 other Sagittas in current registration in the US, but not sure if any has 17m wings. In case you want to check those leads, here's the link with physical addresses. Email addresses can be obtained from the SSA.ORG website if they are members.
Happy hunting!

http://registry.faa.gov/aircraftinqu...TTA&Page No=1