The 'Ultimate Portfolio' book was part of an excellent series published by Jan Jorgensen. There were initially four books, one on each of the Scandinavian air forces, then he went on to do several volumes on individual Saab jets. It looks like they're all gone now though, he used to sell them through his own website (from where I got most of mine) but I can no longer find it. It's a pity - mine would definitely be on the list of 'things to grab on the way out if the house went on fire'!
I agree that a Daco book on the Viggen would be great, though the HMH book (which I'd forgotten about) is actually along the same lines and is pretty good.