The crate would have just a few items from the contraband crates in one, though it'd probably be expensive (40?) due to the nature of having those items in one place. Probably also part of that is... you probably are REALLY ordering something worth 40 for 'your guy' who takes it as payment and swaps it with the predcrate.
Fluff aside, I was thinking it could contain:
1x Parapen (/obj/item/weapon/pen/paralysis)
1x Cloaking Device (/obj/item/weapon/cloaking_device)
50/50 chance of an additional parapen, or a neurotox beaker (/obj/item/weapon/reagent_containers/glass/beaker/neurotoxin)
How's that sound?