Alright, so I failed my little self imposed challenge. But not for the reasons you guys suggested.
The bottleneck was not alloys. If there's anything I'm good at, its working with very little; I only manufactured 6 suits of skeleton armor and 5 laser rifles. The remainder of our arsenal was made up of minor equipment like medikits as well as gear captured from the aliens. Maybe this would have been a bad idea in the long term, but we were facing down cyberdisks and berserkers without casualties (well, usually. None of the important soldiers died, although many were wounded). The remaining enemies would have either have no more health than a cyberdisk or be vulnerable to HEAT ammo, so I think we could have gone to the end of the game provided we kept the experienced soldiers alive. Especially our ONE psychic soldier, a support colonel. Losing her would have been the end.
The main bottleneck was actually research time. I beat the alien base with good gear and a relatively safe world, but then found myself facing down 3 months of research. I needed the three techs required to build a firestorm, the hyperwave beacon, and I really wanted LPRs (I'd stolen 6 of them) and plasma cannons for the firestorm. And of course firestorms take two weeks to build. While I did fail a terror mission, I ALSO managed to get lucky and catch an abduction craft, and I only ever failed that one terror mission. This is definitely doable; if I try this again I'll go Europe and build multiple laboratories and workshops in the place of the satellites I usually build. I don't need instant autopsies and interogations, because all I really need from is a little research credit from sectoid, floater, and maybe muton interrogations. I might trim some more fat off my army; maybe I'll skip lasers or something. Or I could go normal mode. I do have one vital question: does taking down the Overseer UFO give panic reduction the way the alien base does? Because that would be WONDERFUL.
For anyone who wants to try this, I have a few tips. You're main problem is beating the game crazy fast, but I've already gone into that. The other headache is income; you have a very fixed stream. You only get one satellite and you better get at least 150 income out of it. Watch your monthly expenses, although xcom can kind of be powered by selling stuff. Do the alien base mission as soon as possible so you can go on to the next part of the game, and also use it like you would use a satellite (at the end of the month, and to stop 5 panic nations from leaving). Heavies are your friends, as they can kill essentially anything with their default gear and their abilities increase their damage output. This applies to snipers to a lesser degree, and maybe shotgun assaults, although revealing aliens is a good way to get yourself overwhelmed. Your operation is going to be powered in a big way by abduction rewards, choose very very carefully because your decision will both determine your rewards (money and engineers are both a good bet) as well is which nations panic. Choosing right is vital in this because abduction missions are the only way you can reliably influence panic. Remember that each nation saved loses 2 panic, each not saved gains 2, and each on a continent not saved gains 1. This means that larger continents should be saved more often.
One last funny story, the game gave me two female soldiers that looked identical except for slightly different hair color, with similar names, in the first mission. Then shortly afterwards it gave me another UK woman that looked pretty similar. So I changed two of their last names and the Hill sisters (Pixie, Wildchild, and Angel, all nicknames given by the game) became our most effective soldiers. The fact that two of them were supports with 3 medikits is probably why we had so few deaths. Pixie was our psychic, and almost certainly would have been the spoiler had we gotten that far. They all survived, as did nearly everyone else. Well, assuming the aliens didn't just kill off xcom, but given that
Pixie is the end result of all their work, I imagine we have at least a minor bargaining chip. Or one person that the aliens want to work with, at least. I'm a little iffy about the alien's motives in general though.