I second the above comment. They look sorta like Valks, but are wider. Great battle scene though, using it for my desktop.
Edited after zooming in. Chaos Dwarves! My mind is blown!
They're built off a landspeeder and about the same size from the looks of things.
Very interesting Diorama, I'd love to see more of the army. Top class work!
The land speeders are converted to look more like vendetas and the army was a throw back SQUATS army using IG rules. The mini Vendetas where the 40k version of Gyrocopters and they where treated as Chimeras.