Instead of carrying the material stuff, the ship's databases carry
holograms of them, turning the Holoventure Zones into a kind of almost in-
I think that might be fine for fashion and some other applications but one thing to remember is that if you're demonstrating 40-ton dump trucks or mining machinery to frontier miners, or new threshing equipment to farmers, new catalytic cracking equipment to oil prospectors, or for that matter, new fish-herding technology to some fine people on Pharos ... or once-farmers-now-community-representative types, these men and women will know what they're doing. They'll want proof that this stuff works, not some virtual reality demonstration of how it should work. I'm sure colonists have seen plenty of stuff that should work but doesn't.
That's why I think, even if the embassy ship has to be followed by a caravan of freighters and the cost of ferrying down samples (then hauling them back up) would be a lot, they'd still bring actual examples. People like this tend to be obsessively practical and refuse to trust anything they can't touch and see working. In fact, if the rep signs up some demonstration, locals might challenge it to a test against their existing equipment.
The examples might be on a smaller scale if they reps think they can get away with it, but these reps know they'll be pitching to a tough crowd who are looking for value and endurance and tend to be penny pinching so you'd probably see a shuttle landing with a 40-ton dump truck slung underneath it. Of course, the corps aren't stupid - even if they're not actually trying to cheat the colonists (a bad idea for repeat business), they're going to do everything to stack the deck in their favor. Photogenic men and women - even in a "good-cop / bad-cop" type thing playing to frontier stereotypes. The older and careworn but still handsome miner in his (deliberately) worn work boots and vest and dinged helmet accompanied by a young, pretty, and very knowledgeable glasses-wearing female engineer. The woman would give the 'hard science' demonstrations, while the older guy would play the "hey, I'm just like you, I wouldn't work for these people if their products weren't better, let's you and I take this thing out for a little unauthorized wear-and-tear during the offhours tonight..." type schtick that would be so well done that the colonists would find themselves buying into it, even if they knew they were being pandered to a bit.