You could pickpocket the items you want her to wear onto her, and see if she takes them automatically. Alternatively, if she can be recruited as a follower, you could trade items with her and chuck her some fancy gear.
That's what I did with the Shiv, which to be honest didn't make a ton of sense that she even took that considering it does less damage than the pickaxe. She wouldn't equip either the Fine Clothes or the Leather Armor that I reverse pickpocketed though. Also, she's not available as a follower =\
I've been grinding on it for 2 nights now, i'm around 75 pickpocket.... i'll report back. Aside from trying to get my wife naked, I'm pretty happy with my new found pickpocket skills.
Cool, definitely reply back to this topic when you get the perks to test it out. I'll keep this thread bookmarked.