An image has surfaced, showing Devastator more upright, and 7 of the Constructicons. The vehicle modes are photos for reference to the animators, but almost all of them have robot forms, including Overload (robot mode didn't appear to feature in the movie though). So maybe there is hope for at least 2 more of the Constructicons as toys (Overload and Scrapper), but probably no hope of a Hightower toy, as the picture suggests that the Movie people didn't even bother generating a robot form for it.

I tried to locate the original asian source of this image (I found 2 links, but neither had it, so maybe it has already been taken down), so have posted a link to a mirrored copy here at tformers.

edit - one asian link worked, but only shows a small version of the image. There is a larger Res image out there somewhere.

For anyone trying to remember which Constructicon is which:
Excavator - Demolishor/Scavenger
Articulated Dumptruck - Overload
Wheel Loader - Scrapper
Cement Mixer - Mixmaster
Dump Truck - Long Haul
Bulldozer - Rampage
Truss Crane - Hightower
Combined form - Devastator