Hmm..Joanna? or something along that line. Jeremy Tankard's Kingfisher?

I could imagine to choose a serif type that more or less strongly picks up the square shapes of Isonorm:

The extreme way: Berthold City, Midnight Kernboy

The subtle way: Melior, Renault, Zapf Elliptical

(all available on http://www.myfonts.com)

Regards,

formschub (Thomas)

_______

Design means: thinking comes first.

I have a question though, is there a reason for using two sans serif faces?

I like the suggestion of Joanna, but I think Scala is a better Joanna as Martin Majoor designed it based on it.

I'd also try Rotis Serif and Thesis Serif. Centaur would be quite interesting.