We need a custom mattress for our co sleeper (long story - I'll spare you the details).
Tetra Tea Tree seems like a good option as they make custom mattresses and we're really happy to pay for all natural materials and for the fact it is made in Australia.
My only concern is that I've read the mattresses can be a little lumpy and some online reviews have questioned whether they are firm enough to be safe for an infant.
If you have a Tetra I'd love to hear your thoughts. If you know of another manufacturer that does custom sizes for baby mattresses I would love to hear about them too.
DD Dec 2011, DS July 2013!