I looked at the sidecar cribs such as the Arms Length, but my research showed people complained that their little ones grew out of them too early. And they're expensive in Australia. We decided against the things that go between you both in the bed like the Snuggle bed as a) ours is a double and b) Mr Duncan is an 'oblivious to the world' sleeper - also they become too small quickly.
We finally decided to sidecar a cot after looking at lots of blogs etc. I mainly went from the info on this site http://www.freewebs.com/
sidecarcrib/ but I found a few other website and remember there was an ikeahacks tutorial somewhere too.
We bought a cheapie IKEA cot/toddler bed (so it would be stable with only three sides) and removed the side, but kept the height at the highest level. The cot mattress is mashed into the side of our bed and we have jammed a cut down pool noodle on the far side to keep the mattress from moving and prevent any gap. The noodle fits inside the fitted sheet along with the actual cot mattress.
We have the cot sitting on some old phone books to bring it up in height a bit but it is still a few cm lower than our bed. Because they say you should sleep babies with their feet at the bottom of the cot Pickle sleeps by my head, facing the other way to me, but its really easy to pick her up and slide her across for feeds/more burps/cuddles.
As she's getting heavier to pick up I plan to make some sleep sacks soon to keep her warm and then she can sleep facing the same way as me and I can just slide her across for feeds without having to worry about blanket safety.
Most of the examples I found on the internet sandwiched the cot between the bed and the wall. We have attached the cot to the bed with bungy cords underneath which is better for us because it means we have access to the cot without having to go via the bed. Much more convenient for nap times, a bit tricky for bed-making. I also bought a couple of over door baskets to hang off the cot to hold toys/books/burp cloths etc. While she is still swaddled and not moving I am basically using the other end of her cot as a bedside table - thats where my glasses, phone etc go at night.
For the first four weeks it was difficult for me to sit up or turn in bed due to the c-section, so Mr Duncan slept next to Pickle and handed her to me for feeds and put her back down/settled her. That was a bit tricky, Mr Duncan is a very heavy sleeper so I'd have to go through a big drama just to wake him to get her up, even if she was crying. He also falls asleep really fast (frequently mid-sentence) and I found both of them slumped together fast asleep a couple of times where he'd fallen asleep halfway through the passing her back manoeuvre. At least she has his sleep skills! We have now swapped sides again. It is so good to be able to see her and listen to her breathe (I'm still having 'is she still alive' paranoias) although man, babies can be noisy sleepers!
I'm really happy with our choice as it gives the co-sleeping benefits and minimises the risks. We wont need to transition her to a cot later and when she's a bit bigger we'll replace the side and move the cot to the other side of the room before moving her to her own room once she's no longer breastfeeding through the night (timing undecided, I *want* to bfeed her for as long as possible but also bfeeding is contraceptive and time is not on our side for any sibling conception).
Here is a link on safe co-sleeping - http://cosleeping.nd.edu/safe-