Anybody who's ever played an RPG where there are items to affect shop prices knows how incredibly annoying it is to shuffle items back and forth just for shopping, and that's exactly what this would do. Making people play inventory managament for minor economy bonuses is awful.
So don't make anything that gives bonuses to shopping? I don't think any of the suggestions even did that - it was all stuff that'd matter out in the world.
I'd definitely be in favor of something like this, though, especially if it includes some new weapons that are more utility than weapon. Let us get some use out of the weapon slots on civilian ships that will never see combat!
How about even adding some combat-utility 'weapons'? Maybe a large energy slot 'sensor jammer' that can stack with the ECM hullmod, or... hm. No, actually, I'm not coming up with any other ideas that seem like they'd be reasonable for combat utility. Ah well, perhaps someone else will think of something.