Check the knob operation of the range first. We have a DCS range and Gaggenau cooktops with front control knobs, and all require that the knob be first pushed in & held before it can be turned on. By the time a child is old enough to manage to do this, s/he is old enough to understand to stay away unless supervised.

Did you ever find a solution to this? Little hands can easily push and turn at 15 months.

Dunno the answer to the question about knob covers but I'm recalling that Trevor's company, Eurostoves, came out with aftermarket locking knobs for prostyle stoves a couple of years ago. I think the link is here is you want to check them out as a possibility : http://www.rangesafe.com/