Well, as part of my Loganwing army, I tend to equip my terminators with combi weapons making them initially nasty when they first hit in the drop pod. So, with the only combi storm bolters I was aware of currently made by forgeworld on the heresy style terminator armor, I had a go at it...
So, in order to actually make a combi-melta storm bolter in this case required a storm bolter, melta gun, and standard bolter.
What I did was first cut off the barrels of both the bolter (really more a barrel tip) and melta gun, along with the "barrel" section of the storm bolter. I then applied the barrel of the melta gun, along with the barrel tip of the bolter to where the barrels would have been on the storm bolter. After shaving off some wolf insignia on the side of the storm bolter, I applied the melta gun "tank" as seen in the third pic... Next ill be working on the combi-plasma storm bolter, though that may take a little more creativity.
I also have a number of ebay auctions going in with 1 day left if your intersted:
Space Marine Predator - only primed - 25$
Custom Converted Dante Model - 13$
4x painted thunderwolves with rider legs and 1 painted lord - 60$
New On Sprue Razorback - 24$
2x New Land Speeders on Sprue with Cyclone Missile Launchers/MM/H.Bolters - 44$