Our schola director has bought the book shown on that website, so I can attest that it really exists in print. The website he linked me to is this one. Hopefully that website will work for you.

I will warn you though, the reprint is even more of a brick than the Liber Usualis, and not in a good way. I borrowed our director's copy for a few weeks to give it a try. The sheer amount that Solesmes managed to squeeze into the book is great, but the scale of the reprint in impractical. It is a smaller trim size than the Liber Usualis, making the chant super small, and straining on the eyes. The paper is also not quite as thin as the Liber, so the book is really thick.

The dimensions are given as: 11.5cm x 16.50cm x 7cm

2290 pages is hard to make ergonomic no matter how you slice it, but perhaps if the trim size was a bit bigger than the Liber, not smaller, and thinner paper used, it could become a real successful seller with a bit of publicity marketing.

Is there a real need to put all of that in one book?

By the way, we do offer it as a download:
https://media.churchmusicassociation.org/books/massandvespers.pdf

I agree, they really don't need to be. The English and other Missal bits are a nice touch to the simple contents of the Liber Brevior, but yes, two books makes more sense. I'd also say perhaps all the Ad Libitum chants in a third book, along with English hymns and whatnot, because a lot of those I might want to use for both Mass and Vespers.

We use English Hymns at Vespers every Sunday for the procession of the priest and servers, plus a recessional on feast days. With Vespers itself being completely liturgical Latin chant, the devotional English hymnody adds some nice variety. And we don't do organ for Vespers both because if I play the organ there will not be enough strong singers leading in the pews, and because I think it is better for people to be confident singing Vespers acapella, that way when we do have Vespers accompanied it is a festive treat, not a crutch that they have grown up on.

No, I am not saying that English hymns should be included in a book for Vespers. The Vesperale should have the whole of the Office chants and nothing but the Office chants. What I am saying is that English hymns should be in a book with the ad libitum chants meant to be sung by the congregation (Attende Domine, Te Deum, all the Benediction chants; the sort of stuff included in the Parish Book of chant). The reason being, that these hymns and chants are utilized (by our parish at least) at both Mass and Vespers. So for Mass you can use your Graduale plus your book of extra chants+hymns. For Vespers you can use your Vesperale plus your book of chants+hymns. That is what I am saying, because it makes most sense for the music I envision using. For Mass polyphony you'd use a separate book/binder, and for Vespers I would seldom (if ever) use polyphony.

Regarding singing English hymns during processions at Vespers, and our choice to chant Vespers a cappella, I will have to respectfully disagree. I am not saying that the organ is only a crutch, just that (at least for some congregations) it can become one if it is used to accompany all the time. The organ is a beautiful tool for coloring the chants and adding a festive taste, but I don't wish for people at our parish to get the idea that accompaniment is crucial to chant itself.

I think, Matthew, that most of our differences are because of a different liturgical culture. Yes, we both favor the traditional Mass, the practice of Sunday Vespers at a parish level, singing full propers, and so many other things; but even within all that it seems we fall on opposite ends of the same spectrum. Moving away from morals, love of tradition, and so many other points on which we agree, the difference is a cultural one. Your ideas are strongly influenced by the traditional French ways of doing things. You love the French traditions: the Institute of Christ the King, the Solesmes method, extensive use of the organ. That is not the culture in my family or in my parish. We are an FSSP parish, our pastor is not French, and neither am I. We are more German. I love the organ, but I don't want to use it at Mass as the French do. They are quite welcome to, and I shan't stop them, but it is not what we do. I can sing the music at Mass mostly a cappella, and still let the organ have its "own voice" by using it to play a Bach piece. I say all this, not to strike up and argument; quite the opposite. I've found we often disagree on many small things, but with the utmost charity, I propose that these differences arise from valid cultural variations within the spectrum of traditional Catholic Liturgy.

Also if I may:

I prefer the propers a capella in part because they’re a pain to rehearse with the organist.

With the ordinary, it takes way too much time to learn chant a capella that the people are invited to sing, other than the simplest chants (and they can’t be guided along faster…). By the time that they do, you’ve changed seasons. But I like the sound of accompanied propers quite a bit; in the right circumstances we would do them from time to time.

What I don’t have a lot of time for, and I’m not saying that you’re doing this here or elsewhere, (I respond with future readers in mind quite a bit) is the idea that the organ is at best superfluous; it’s snobbish and more than a bit grating.

But again my experience is that people will surprise you with what they can do, even if the organ is used as support on a regular basis. It’s mostly (but not for every single ordinary I grant) not a problem if the organ breaks down at this point.