Can you reposition the lever on the splined shaft? Or have I misunderstood the question?

I've seen them bent upwards...  yours looks pretty good though.  I don't think there's a factory adjustable stop but I suppose you could build up lever or peg to lower to suit you or make something adjustable.

Another thought is to adjust your other bikes to match the pedal height on this one and it will likely stop being a problem after a little getting used to.  That's what I've found works for me.  And a little higher like the stock RT2 helps avoid accidentally braking...  especially on rough trails. 

Or you could use a vice, some heat and a large hammer…