LN2, LOX, and in fact any liquid that is in gas form at STP (Standard Temp/Pressure, 25ºC/1 atmosphere) will expand VIOLENTLY when it is stuffed into a container and heat is applied - and in the case of LOX will present a serious oxidation and fire hazard.
Carbon fiber alone will not work easily for a high-pressure storage tank. It will need reinforcing bands on the walls and additional strengthening at the seams, or you will need to source a tank purpose-made for high pressures. Polycarbonates also will not work, if only because the container walls will need to be extremely thick to contain such pressures.
Normally when LN2 is used for overclock cooling, they stick it into a deep copper cylinder with a closed bottom, which in turn rests upon the CPU. The LN2 that has taken in the heat expands and rises out of the tube, and more LN2 is poured in. This is a system that was developed purely for setting records, not day to day use. LOX (and any other gas) would use the same method.
LN2 was used in certain Cray machines several years back, and they used a compression recirculation system - exactly the same principle as a fridge, only designed to handle higher pressures and temperatures. This cooling strategy has been seen in PCs before, known as 'phase change' cooling. It is called that because the working 'fluid' changes phase from liquid to gas, and back again. This is about the only method you would be able to use for a high pressure gas system that recirculates the gas.
Hope this helps.