I think careful selection of many of the fun products from
Pottery Barn Kids could inspire amazing steampunk or diesel punk kids room. The many bedding collections of trains, airplanes, and nautical rooms are a nice break from the overly cutesy baby and kids themes I see on most stores. I adore my baby but "precious" isn't how I want to decorate my house! Here are a few of my favorites from the current catalogue. What i don't like about Pottery Barn is that most of the items are made in China. They look great in photos but I often find they aren't made all that well when you see them in person. Many of the items like the toybox and shelves could be handmade with basic skills and probably last a lot longer. This is why I suggest using these images as ideas but not as product recommendations.
Here are train themes for steam punk decor .... there are also cute bedding ideas etc
There are old airplane themes for diesel punk ideas ...
There are so many great lamps that its hard to choose from them all. Each could work for different rooms. They have lamps inspired by ships, trains, train stations etc. The nice thing is most are classic looking lamps that can be used long after the baby room has to go or could be relocated to other rooms. Again they are all made in China too, i bought a lantern and had to exchange because the initial one was broken. Alas making one's own lamps is not as easy so we're stuck buying them .
We picked the larger, plug-in version of the lamp above but that isn't in the catalogue anymore.