Thanks in part to our friends at GamesRadar, we noticed that there's N7 armor stashed away in Mass Effect: Andromeda's research screen. Research it, build it, and tweak the colors, and you've got yourself the classic Mass Effect trilogy look. I miss Commander Shepard, but given that she's probably not going to show up in Andromeda after hundreds of years—she's just dusty old bones at this point—I can at least pay tribute with some red and grey armor.
First, you'll need to collect a bunch of Milky Way research points. These are mostly acquired by scanning technology, so peer through your scanner's orange window often to see if there's anything you can catalog. Once you have 250 points you can research the whole armor set.
Head to a research station—the one on your ship is located at the central table, with the AVP and Strike Team terminals—and find the N7 armor set under 'Milky Way Technology.' Research them, back out of the research menu, and then head to the development menu. Here's the hard part: to build this classic carapace you're going to need a lot of Omni-Gel canisters, copper, iridium, and platinum.
I'd collected tons of Omni-Gel by the time I researched the armor, so the metals are the hard part. Platinum can be found on Kadara by using the Nomad to mine, and there are copper deposits on both Kadara and Voeld. You can also acquire raw materials by breaking down weapons and armor from the inventory screen, which is how I got most of it—play long enough and you'll collect a lot of junk. The hardest element to find, in my experience, was iridium. I ended up having to buy it from the general merchant on the Nexus. It's expensive, so you may have to sell off a bunch of junk to afford it.
Once crafted from the development menu, equip your new armor (you can do that at the airlock by the bridge of the Tempest, or before landing on hostile planets), and head to your quarters. There, you can customize the colors. A selection of greys from dark to light for colors 1-3 and pattern 1 in red does the trick pretty well.
Ta-da: You're Commander Shepard again. Sorta. Not really. But the armor isn't bad, with each piece increasing biotic damage and max shields, and the chest piece also decreasing biotic recharge speed. And wearing such well-known armor can have a different kind of effect—I'll let you discover what I mean on Eos.