You know you can turn a normal full sized cot or cotbed into a larger version of the next2me.
Any cot can have one side removed to make a 3-sided "sidecar cot" (Google images if you don't know what I mean). Then you just wedge it up to your bed.
I used a sidecar cot from birth with my 4 children, didn't bother wasting money on the extra furnature of a smaller sidecar crib. It helps get them used to having their own space, but with Mummy able to cuddle right inside the cot.
That solves one side of the bed. For the other side, a pool noodle under the bottom sheet makes enough of a ridge to stop baby falling out of bed. Pillows on the floor help for accidents - preferably large/solid pillows like those on a sofa for example.
Regarding you going to bed - I'd suggest setting up a dressing room (of sorts) for you in a different room. Nursery makes sence if you're not using that room. You could move your chest of drawers into the other room, maybe even your wardrobes (creates space for the big cot and floor pillows in your room). Add in a clothes horse or similar and basucly use this room for getting ready/dressed/undressed. Then you're literally just getting into bed and going to sleep in your room.
Finally, I know you didn't really want an answer, but (how do you know they aren’t thirsty?!) - a properly hydrated child (and adult) should not be waking in the night due to physical thirst. If they are, if you were, then they are very, very dehydrated and need to drink much more during the day.
Your baby is waking in the night for comfort - and that's ok. But she is not waking due to thirst, well not assuming you have a healthy diet including enough fluids in the daytime. Needing comfort is equally as important as needing fluids, I am not suggesting not feeding. But don't kid yourself as to the reason for the night feeds - they are 100% about comfort not calories or water.