In addition to 'raw' size, you need to add legibility as well as readability issues. It's no use to have a minimalist design, if the user a) can't see what it says (or is a microscope expected), or b) can't interpret the symbols he/she sees (are they too artistic or too far out?).
The first possible typeface that comes to mind is Adobe Cheq -- it is not perfect as it has some details that may cause problems (such as the curved bases of the pieces, the very curvy knights, and the very narrow 'holes' in the black King).
Linares is a slightly less useful typeface: it is open, but it has a lot
of small details
If you are thinking of designing a typeface:
The production mechanics enter into the question. Are you dealing with pixels or lead? Will those pixels stay as they are, or will any kind of scaling get applied, affecting legibility? If print, what quality paper are you using, and what line resolution does it have? If you try to print higher resolution, you're likely to see that details get lost or artifacts (such as doglegs) get introduced. Additionally, contrast between glyph foreground and glyph background if any is important: I currently see lots of old typefaces where white Bishop on black square are almost illegible due to lack of such contrast.
There's a lot of work down on typefaces for newspaper printing: these must work on newsprint paper (so no tiny details), and they need to print clearly at high printing speed (so they need a fair amount of background white 'inside' to separate details.) Bitstream Oranda is a fairly well known example: very 'light', very 'open', and rather robust. Cheq tends in this direction.
You may also want to consider sign typeface design: they typically emphasis very high legibility and clear 'differences' between characters such as S/8/5 and 1/l/I. The one I know best is SISPOS by Bo Berndal; there's
a wiki page for 'list of public sigage typefaces' for additional inspiration.
Typefaces intended for low-resolution use, such as Lucida Fax are often
useful for this type of use, as are optically 'small sizes' (6pt and less) of digital typefaces.