What do you get if you take 30mm out of the barrel of a G2? A G2 Pixie, although the pen itself seems think it's called a G2 XS (and in other markets it's known as the G2 Mini). Identical to the normal G2 in all other respects, it has the G2 virtues of excellent grip and smooth densely-coloured retractable gel ink refill, but in a compact format that's handy for pocket or purse.
"Like a G2, only shorter" is the marketing message that didn't get used. Instead we have "So tiny... So Pixie". So there.
Unfortunately, refills are not likely to become available in the UK.