When I started my salamanders I decided to make my swords look 'master crafted' to represent their blacksmithing culture. I did this by making them reallllly big.p.p.s. how could i go about master-craft-ifying (word!) a melta/flamer other than just painting it gold?
I'm not saying this is the best idea, but they definitely stand out, so i would recommend moving the barrels about, making them longer, adding extra gubbins - basically anything which makes them appear different to the standard item.
Another idea is to use bits from the Lizardman sets to add scales or salamander heads to your guns.