For almost a year now, Toranoana has been having gallery exhibitions of popular artists, and at these events you can buy a large B4-sized 'pamphlet' that includes the artists' works that were on display in a book format. Alpha's (有葉) gallery was the most recent one, having ran from May 19th through the 28th and the amusingly titled Pictures at an Exhibition of Alpha was the companion pamphlet.
Like with Tony Taka's T2 Gallery, Pictures at an Exhibition of Alpha is also B4 sized, but it isn't hardcover. Instead it's softcover, and staple-bound with a slip on cover. It's 64 pages in total, without including the covers and the cover illustration is included on the inside without text.
Through a bit of bad timing on my part, I received AKABEi SOFT2 Illustrations Collection and Pictures at an Exhibition of Alpha at about the same time, so the content overlap seemed even more extreme since it was so fresh in my memory. But because the majority of the overlap illustrations are featured in such tiny dimensions in AKABEi SOFT2 Illustrations Collection it doesn't feel like a wasted purchase at all.
In fact, a lot of the best AKABEi SOFT2 illustrations are in this pamphlet, which makes sense since this was intended to be a gallery exhibition. Another plus is that it features the AKABEi SOFT2 Illustrations Collection cover girl from Okiba ga Nai! (置き場がない！) in another new illustration that isn't in the memorial art book.
The illustrations in the Pictures at an Exhibition of Alpha that weren't AKABEi SOFT2 related were either Toranoana originals, or Alpha's original illustrations. Although, to be clear there were only nine of her original illustrations in this collection and five Toranoana illustrations that didn't feature AKABEi SOFT2 characters. Many of the Toranoana and AKABEi SOFT2 cross promotional illustrations are included too, but those were also in the memorial art book, though in smaller sizes.
I'm really becoming a fan of these large sized doujins and art books---it just looks better and ultimately, I'm buying an art book for the style, presentation and quality just as much as for the content. Since Pictures at an Exhibition of Alpha was only sold as accompaniment for the gallery exhibition, if you're interested you'll have to go through Yahoo! Japan Auctions or Mandarake to find it. Either way, if you're just looking for a nice collection of Alpha's illustrations, this is probably a better option than AKABEi SOFT2 Illustrations Collection.