Not sure if this has been done before, but got bored so I decided to do it. I only did DM6-DM9, since I couldn't find a DM3/Trix or DM5. So I decided to stick with the UL versions.
I zero'd out the scale in between every gun. The DM9 is the Claret, DM8 is Olive-Black, DM7 is Clear, and DM6 is Blue. The DM7, DM8, and DM9 are all BNIB and straight out of the package. The DM6 is used, but stock.
DM9=2 Pounds 3.2 Ounces
DM8=2 Pounds 6.4 Ounces
DM7=2 Pounds 6.0 Ounces (Yes it's lighter than the DM8. I weighed them both several times and got the same results each time, DM8 is 0.4 ounces heavier than it's predecessor.)
DM6=2 Pounds 9.6 Ounces
Now onto the length comparison. This was a lot trickier than I thought, since the macro fitting on the side really screws up how they sit on top of each other. I won't take them off since they are all mainly NIB guns. I did my best to line the back of the guns up. They seemed pretty even by eye sight.
DM6 is in the way back, then DM7, then DM8, and finally DM9.
And just because I keep hearing how much shorter the body is on the DM9, here's a DM9 on top of a DM8.
Sorry for semi-crappy pictures, I used my camera phone.
Any more requests? I'll take them whenever I'm at work.