The pic Al posted is the first time we've gotten to see Shia and Harrison together, and I've got to admit the resemblance is there a bit. Especially if you look at it as he's the combination of Indy and Marion. I saw Shia on Letterman last night for Transformers and IJ4 was mentioned briefly, but seeing him then the resemblance was gone. He looked super skinny, shorter in stature, and very swarthy(with some serious eyebrows). The resemblance is only sporadic, but as far as the mannerisms that could possibly link them we'll have to wait and see next May.
Now Ford looked fantastic in the first pic of him in his Indy duds, but with this pic the age factor is more apparent. He looked just more weathered in the fedora, shirt, etc....but in his professor gear the age kicks in. Granted this is a snapshot, not the finished, edited, potentially touched up version, but there is a slight Firewall look to him on the bike. He's still looking good, but older yes.