She's going through developmental changes in her motor skills.
This is common at each juncture of change and growth.
YES, they will even stand in their crib or roll around or scoot around and pull up. It's normal. BOTH my kids did that when they hit milestones too. It does abrupt their sleep.
Its hard to make them "not" stand up... but we need to help them get back down... because sometimes, per their development, they 'cannot' then sit back down and lie down in perfect sequence and posture themselves back into a perfect little sleep position.
It is a "phase" and they will get better at adjusting their physical skills. Until then, it will cause a hiccup in things.
Why not put her mattress on the floor? That's what we do and did with both our kids, and co-sleep there when needed. Our floor futon is in our bedroom. It works for us.
What you would do, is co-sleep w/her when it's nap-time or bedtime, and then once she falls asleep, you can go back to your/Hubby's bed....and or just get up and go do what you want = "me" time.
And yes, as Jacy and the other posters said, why not try a crib? It IS safest... and when she gets older AND more mobile, it will contain the child more safely, especially when putting them down for naps/bedtime.
Then too, its a matter of just letting the phase pass... each time they gain another motor skill, they will then "practice" it, even when they are supposed to be sleeping.... and it's just sort of 'instinctual' that they go through this process. When both of my kids did that... I woke, comforted them, co-slept, or helped them get back down or sit down, and laid them down. It IS repetitive... but so it is. "Growing pains" is also a doozy for the child too... and often it is a combination of things: their changing REM sleep patterns, their changing physical development, their changing cognitive development, separation anxiety, teething, "night terrors" etc. ALL developmental based.
Sleep patterns for a baby or child evolves...it is NOT static. Even for adults its not static.
It will pass...
Or, there are those enclosed child play tents that you can make into a cute little sleeper for her, with a pad in it. Here is a link:
http://www.toysrus.com/search/index.jsp?kwCatId=&kw=k...
My daughter went through a phase where she liked to sleep in hers. LOL (but she was already a toddler at this point, not a baby).
All the best,
Susan