@pavel-s: That would definitely be much higher-level than what I'm aiming for, yeah

.
Basically, I'd draw (ha!) the line at basic drawing primitives (line, triangle, polygons, that kind of thing). I have no interest in doing that myself, but I'd be open for that kind of stuff to be merged in the main lib

.
(c.f., an earlier discussion about immediate mode UI toolkits for some more context).
EDIT: Said discussion is probably in the
Kobo thread 
).