Do you prefer under slung or over slung? Bolter barrel on top or bottom? Should they all have the big ammo box?

The secondary weapon is single shot, so really Underslung works best, in my mind. Still a normal magazine is fine for the Bolter, because it is a normal Bolter.

I concur. Underslung cause it provides that imagry of a machine gun with an underslung grendade launcher. As for ammo size I would say normal mag. It's a single shot weapon so I would assume the underslung has already been loaded in and takes up the room it needs already for one shot, no mag needed.

Well I all the combis I've made up until now have had the big ammo box because they were for Sternguard. But if I was going to mass produce some I was trying to decide which way to go.

Yeah I've seen those, and a whole lot of other designs. I actually don't think the CH ones look very nice. I like the concept of the interchangeable combis, I just don't like their execution.

well, I agree on both points, and the chaos ones are truly truly awful. I like the GW SM ones, but they don't make combi flamers, and the melta/plasmas are only on the commder sprue, which is a $20 model no one buys. If they just released the weapons sprue for $10, they'd sell a million of them and it'd save soo much effort for the player base.

if it's CAD designed, it can be 3d printed for not that much, and if it's pressed, you can actually take like 20-30 pics of it and autodesk has software that'll take the 2d pictures and combine it into a 3d cad model, which, again, can be printed .

I was just talking to chris about combi weapons and all that on saturday - he just got some 3-d printed helmets, and i've seriously considered just buying a printer (they run about $2000), but i guarantee they'll be 100% better and $500 cheaper in a year, so it's kinda eh on that. I'm sure one can be rented (locally or remotely) for not too much though.

Either way, let me know what you come up with, and if you need any help in mass producing it, well, I'd love to get me some ridiculous combi love.

Actually you can get a Makerbot kit for about 1200 these days. Less if you get the components and build it yourself.

Combis will be on of the first things I start pressing when I get my silicone. Combi meltas and flamers I think, they seem to be the most wanted.

Did you ever see my cobi meltas for my Sterngaurd? I have it magnitized and on the top. I used the old lead RT heavy bolters as my base and cut the heck out of them. Main idea is you can pull them off once fired.