Would this be crazy ?

So.. i just bought a D7000 with 18-105 lens.
On the other hand the last week the prices of the d3100 have come down a lot :
389 euro for a d3100 with 18-55 !
so around 300 for the D3100 body (and the 18-55 isn't a bad lens i think ?)

Would it be crazy to buy a d3100 as a second (light travel) body ?
i'd mainly use it with the 35mm