Google "35 inch mattress". For instance, I found this one (35 x 79) that is made for bunk beds in trucks http://www.livingincomfort.com/hg30457.html

It depends on where you live. Here in Austin there is a mattress company that still makes its own mattresses and they will make them to custom sizes. If you look for small mattress manufacturers in your area, you may find a similar situation.

Thanks everyone!

j222b's post was an Eye-opener !

I am looking for a 35 inch mattress as well, near Baltimore. Ikea sells them (standard size in Europe) but apparently not in the US. Fixing up a beautiful vintage bed for my granddaughter. I bought it at a consignment shop 34 years ago.

psshaffer: have you had any luck finding a mattress on internet? The bed sounds lovely. I had an child's antique bed, and I found a crib mattress fit. Crib mattress is 28 x 52.

Google "35 inch mattress". For instance, I found this one (35 x 79) that is made for bunk beds in trucks http://www.livingincomfort.com/hg30457.html

Thanks . The bed takes a full length mattress, it's not a toddler size. Every budget mattress store in the UK seems to carry them, but that's not much help here in the US! My daughter used the bed until she was twelve and we moved to a house where she had a bigger room. She was 5 ft 9 inches by then! The narrow twin is great for a small bedroom, and this bed is a darling half tester (canopy).

In the USA, it seems your best source would be a local mattress business that can make your custom size. I have had two mattresses made this way and they have been very pleased.