From the last order of Warhammer 40.000 miniatures I finally had a Venerable Dreadnought (now that hey are available in plastic and thus cheaper and easier to customize), so when my girlfriend got stomach sick it looked like the perfect night for some miniature assembling while taking care of her.
Having already two normal dreadnoughs (with the bad luck of both with the same multi-melta + combat fist combo), I wanted this third dreadnought to be really different, but the standard is to have a close combat left arm and a long range right arm.
As the kit comes with three choices of heavy weapons (plasma cannon, twin-linked lascannons and assaut cannon), I decided to risk destroying the left arm and modding it to have the twin-linked lascannon to have a real badass venerable monster :D
Here are the results of the (unpainted) miniature:
Basically it was done cutting the original combat fist, leaving only the "shoulder"), and cutting from the lascannons a square to make it fit exactly in the shoulder. For the bottom hole that was under the big cable I used one of the optinal "ammo" packs (with some cutting to make it fit), and finally I did some cuts too in the shoulder armor reinforcement to make it fit with the cannon.
It is not perfect and the arm has a few millimeters more of separation from the body than the right arm, but at least I did not screw it up and once painted it won't be noticeable at all :)