I'm sorry I haven't had time to read this thread in detail. Apologies if this is off-point or reiterating points already made. But I noticed something about a problem with handlebars being too wide on one bike -- you could replace them with something narrower if you end up with a bike that's perfect except for the bars.
I went from a men's Trek 2000 to a WSD Madone in the same frame size but the difference in fit and comfort was huge for me. Different bikes, and certainly not the same geometry for men's and women's. I had the shortest possible stem on the Trek 2000 and the reach was still too long. Also the handlebars were too big to ride in the drops. And I always thought I had long arms -- many long sleeved shirts are too too short for me. With the WSD Madone and the compact handlebars that came with it, I have been way more comfortable. After a few years I got a narrower version of the same handlebar to address some shoulder and neck problems.
The thing is that the Trek 2000 was my first road bike, I had a fitting done before buying it, and I thought it was okay. Until years later I was having a new saddle fitting for it, and the guy doing the fitting pointed out that my shoulders were hunched because the reach was too long. I didn't really understand what he was saying until I tried the WSD Madone. He let me take it for a long test ride because I was concerned about the gearing; after about 10 minutes I understood his point about the reach on the old bike.
So I guess my point is to try to pay attention to your shoulders, neck and arms while you are test riding. With your hands on the hoods, your elbows should be a bit bent. You should be able to ride with your neck and relaxed, not hunched up. Also try riding in the drops -- you should feel comfortable and able to reach and work the brake/shift levers easily.
Re: aluminum frames, my first bike was aluminum and I rode several centuries and many other 60-80 mile rides on it. It was fine and I would still be riding it if the fit had been better.
- Gray Trek Madone 4.7 road bike, mystery crack in top tube repaired by Calfee, Bontrager Affinity RXL saddle
- Red Trek 6000 mountain bike, Bontrager Evoke WSD saddle
Gone but not forgotten:
- Silver Trek 2000 road bike
- Two awesome and worn out Juliana saddles