The guys over at telegraph.com has a report on the reinventors of Davros in the New series. The next generation Davros began life in the imagination of concept artist Peter McKinstry.
"We wanted to get away from the slightly flimsy look of the earlier series," he says. "So I beefed Davros up, made him more sturdy. I also think that the reinvented Davros is unusual for the new Doctor Who because he is genuinely grotesque."
Read it all at the link above.