Suzz1120 it is simple to go from double point to circular if you can find the needle size you need. HiyaHiya, my preferred needle has circulars in 9 inch length from US size 1 to 9 (http://hiyahiyanorthamerica.com/hiyahiya-sharp-knitting-needles-sharp-circular-needles-c-1_873.html?osCsid=d5eae60f4bfd5ebc250296d1629a0ee1 )
HiyaHiya also has 11 and 12 inch circular needles.
There are other makers of 9 to 12 inch circulars I just like Hiya Hiya. I think they are a good value for the cost.
Some people have problems with the size of the needles but there are a lot of us that love them.
As said above you simply put a marker at the point where a new DP needle would start.
You may find you like Magic Loop
However, you do not have to use it:
Originally Posted by suzeeq
You'll have to use magic loop
As DogCatMom said there is also two circular
but, two of the things about the 9 inch is that there is little or no laddering because you never switch between needles and there are no lost of time as you change between needles, you just go around and around.
I say that if there are 9 inch circular needles of the size you like don't put the small size down until you try them. Once you try them you may not be able to put them down.