It looks interesting, but more focused on conversions than actual operations it seems:
octave:37> a.value = 100
a =
scalar structure containing the fields:
value = 100
unit = W
octave:38> a.unit = 'W'
a =
scalar structure containing the fields:
value = 100
unit = W
octave:39> b.value = 3
b =
scalar structure containing the fields:
value = 3
unit = s
octave:40> b.unit = 's'
b =
scalar structure containing the fields:
value = 3
unit = s
octave:41> a*b
error: binary operator '*' not implemented for 'scalar struct' by 'scalar struct' operations
This looks very VERY promising! I'll try to install it tomorrow and Post here the results! Thanks?