This is said to be extremely rare to find and a video of this has not surfaced, though footage once appeared on a defunct Disney wiki page. The photos were taken by user Dinojungle but later removed by the Disney wiki because of plagiarism.
The early preview has a stay tuned bumper with Leo, Annie, Quincy and June sitting in rocket.
The promo itself has rocket flying around places and the Little Einsteins at the playground swinging on swings and singing.
The footage was uploaded to YouTube in 2015 with the names Little Einsteins Promo and Extremely Rare Little Einsteins Early Preview.
The Opening Theme was re uploaded by Bubic Einstein with a Image of the Pilot. Bubic Einstein also got a clip of the preview and cropped out the Image and made it png.
The animation was produced at Boulder Media in Dublin, Ireland.