I want to position list item icons

On my project, the designers have made the specifications of our lists (ul and ol) quite stylized, with the list item icons distanced just a bit further from the list item content than is the default. Achieving this design is not possible with list-style-image, so I need to set their style to none and use ::before instead for this effect, which also has its drawbacks.

It would be great if we could adjust the offset of list-style-image so as not to have to resort to hacks.