i really love Ikea for co-ordinated bedding. I have a boy and girl that share a room, and ikea has a pretty big selection of things from crib/toddler to full size that co-ordinate with each other but in different colorways.

A few years ago I bought striped bedding from them that included a pink stripe. for my boys bed I played up the greens and blues, and for my girls bed I played up the pink. We are moving into a little bit older age, and are going to use a ticking stripe from Ikea, In red (that reads pink when seen from afar) for my 6 year old daughter, and green for my 9 year old son.

We are fortunate to be able to have them in a big room, so both of our twin beds are on the floor, but when they were in a smaller room we had a short loft bed (adult chest height) with a toddler bed underneath. That worked well for us.

http://www.ikea.com/us/en/catalog/products/10123996/

Is a short loft bed

I would invest in coordinating quilts or something similar. It's kind of silly to buy matching crib bedding to the toddler set since you might not be using it for a long time.

I would start with a basic like grey or brown and add additional colors to distinguish each child.

http://urbout.co/npsuD6

http://bit.ly/osiUIh

Solid colors always work. Also, there's no need to be "gendered." I'm a woman and I don't wear pink and flowers all the time. Why do they need to be "boy girl" and yet coordinate? If you want them to match, let them match!

Aren't the mattresses for toddler beds the same as for cribs?

I'm not sure if it's your style (or price range) but Pottery Barn sells coordinated bedding both for boy-girl rooms and crib-toddler bed rooms.

Garnet Hill has a lot of cute stuff that could be unisex and comes in crib mattress size as well as twin/full/queen.

What about building a small platform with casters for the toddler bed to slide under the crib like a trundle, will open up lots of floor space for day time play, and will make it easy to put the bed where ever is best for sleeping.

I am in the exact same dilema. My plan is to use blue polka-dot (white with blue polka-dots, not the blue-on-blue set) Land of Nod crib sheets for both the crib and toddler bed. For the boy, to be born in December, I will use the construction themed bedding. For the girl, 2, I will use the blue "With a Flourish" bedding. The blues for both sets work together. I will add accents of grey, orange, and red. I think the unified color scheme will pull it all together. I will let you know in a couple weeks, when my plan is actually executed, if I was able to make it work.

Meh, I guess I don't understand the big issue with genderizing bedding and nurseries. I like to gravitate to things kids (of any sex) love- lots of color and whimsy! Can't go wrong with that.

I don't know if you're looking for different furniture ideas, but what we're planning to do, is have our DS who just turned 2 this summer, sleep in a loft bed, and have the convertible crib be underneath. My FIL is super at custom woodworking, and so he's going to build it, and have stairs on the side instead of ladder. This would save on floor space, and the loft bed would grow with either child. We don't know the sex of our peanut yet, I'm just 14 weeks, but we're in the same situation trying to figure out the shared-room thing.

I think it helps to have some space between children's beds so that they don't wake each other up too much. Sleeping children = happy parents! Our 3 year old and 1 year old sleep in the same small room, but on opposite sides (and the 3 year old still likes to make a lot of noise to wake up the 1 year old when he gets up first!).