How about the drive capability of your output voltage?If you need high drive capability,a DC/DC or a charge pump would help you.But I think it's a hard work for a DC/DC to do the job.
It really depends on your output current requirements. You can use a regulated charge pump or an inductor-based boost (step-up) converter. A regulated charge pump is only useful up to a few mA and is relatively inefficient. Are you designing an IC or are you designing a power supply? You can buy boost converters from companies like Linear Tech, Maxim, National, etc.