I built nine of them, three with rokkit launchas, three with grotzookas and three with kustom mega-blastas.
Six were built using the newer kits, two with the old metal killa kans and one with the old metal dreadnought, which I turned into the Killa Kan Goblin King.
There was a lot of conversion to replace all the missing bits, as I only bought a single box and traded/bought extra bits to build the five others.
Here are the pictures for five of them. The four others will be added later when I get back to them for basing and primer.
(yes those are nuts)
For my lobbas, I use old school squig katapults.
The only conversion I did was to sculpt the buzzer squigs clay pots that are used as ammo in the 2nd edition codex fluff.
I scratch built all three of my zzap guns from left over bits, toys and green stuff. The result was nice and all three are unique.
I will add the krew to my big guns here as I convert and paint them. So far I have only one painted grot I have pictures for. But I will add the others later.