If you look on this website scroll down to the colourful embedded spreadsheet ) it mentions every 787 and the current status ( not sure how often it's updated but it has changed this week )
http://nyc787.********.co.uk/
Whilst this website shows daily pictures from Paine Field - Everett where the Thomson 787's are based. When they're taking off for test flights i'm sure it'll show on here.
http://kpae.********.co.uk/