We have been going through this off and on for about a year. We (like you) ended up with raging tantrums at 3am or so when we turned her around and took her right back to bed, and it just wasn't working. It tends to come in spurts, seemingly when she needs a little extra reassurance and comfort. Currently, we let her come into our bed, and one of two things happen. 1) We all fall asleep and then when I wake up after my next sleep cycle, I pick her up and put her back to bed. She doesn't wake, and
usually she stays there until morning. (We find that this method helps us all maximize our sleep, even though it's interrupted, because none of us operates nicely on low sleep). Or 2) she is restless and doesn't go back to sleep, tosses and turns. I take her back to her bed, whispering to her that she's having a hard time falling asleep because her bed is more comfortable for her. I then pretty much try to fall asleep on the foot of her bed and then go back to my own bed after my sleep cycle ends (about 45 minutes it seems). This also seems to work for her.
I had thought of putting a blowup bed next to ours, but our bedroom is small, and I wasn't too crazy about having a space in our room that she felt entitled to--I envisioned arguments at bed time about why she couldn't go to sleep in our room instead of hers...
In any sense, I tend to be able to fall asleep more easily than others it seems, so this works for us. It is the least stressful thing to do for our family, and I figure since she's not a snuggly type of child anyway, I'll take the cuddles when I can, even at 2am and asleep.
It's rough, but you'll find out what works for you. Good luck!
