I am in a very similar situation and very disappointed. I just entered Progressive era. I have no Progressive units and very limited (some zero) Progressive goods to negotiate. I can not obtain any Progressive units, as I do not have enough Progressive goods to get through the tech tree. I will put Industrial for Progressive trades on the Market (but in Beta trades are very limited and my guild is small). It appears this quest maybe the end of the line for me too. I will try to make trades, as the Negotiation is my only option in this quest. The real quest kicker, was when I used Industrial goods as a trade, "no" Industrial goods (all red, and rejected). Then I had no chance, when my only option was to use Progressive goods. I have been playing for almost 3 years and do not foresee getting past this one quest (unless I can get those trades at the market). Possibly, the developers will reconsideration this situation, in this quest, when it rolls out to the other worlds. If not, hopefully the other trade markets will be easier than Beta or more people will not be able to get past this quest.