Dave, am not sure of the video you're talking about, but in the Pennsy Power books by Staufer their are photos of multiple Is in action, pushers included.
Regarding the L1 Mikado and the I1 Decapod, has it been confirmed by Lionel that both are based on the former Premier dyes that MTH sold to Lionel? If so, am curious if these includes the drive-trains and all mechanicals? I would think yes but am far from an expert on the guts of electric trains and "the what and how" of the sale/transfer of such property includes.
The reason I ask is because as an owner of the Premier I1s I can verify that they are very-well engineered machines, although that observation is anecdotal as I've only run the heck out of them and the only maintenance I've performed is lubing and traction tires, nonetheless it'd be reassuring to know that the Legacy version will have the same mechanics (albeit Lionel is using Canon motors instead of Pittman) just different control and sound system.
FWIW: I've performed a visual check of my Legacy PRR K4s and Premier Decapod; and assuming Lionel uses the K4s boiler on the L1 Mikado, I still cannot understand the large price difference between them based on boiler size and detail alone. However, it is possible the Decapod drive train is more complex than the L1 Mikado (10 wheels vs. 8 wheels) and if true would warrant a higher price.
At the end of the day, and despite the price, it is exciting for us PRR fans to see an O-scale model of the Hippos with Legacy and Railsounds. MTH last produced their scale model in 2006, and their very-well-proportioned design will live on. The Hippos were a staple for the PRR and were a tremendous freight mover and lend themselves well to double and triple heading 
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