THE PATH:
For the longest time, it seems, I've been looking for a journal with the following four characteristics:
(1) Large (U.S. letter or A4) UNLINED pages;
(2) Fountain pen friendly paper that will allow writing on both sides;
(3) Must lie flat (I don't care if there aren't too many pages in a volume); and
(4) Must not require me to write into or out of a "hump" or into a wire binding.
These requirements don't seem too difficult to accommodate, but I've had the hardest time finding something.
I started out with Mead sketchbooks, the kind that are wire-bound at the top:

Couple of problems: (1) Since it's wire-bound at the top, it's hard to write on the "second" page. For a while, I'd write on one side till the end of the volume, then flip the whole thing over and write on the other side. Then Mead seems to have changed the "formulation" of the paper and ink would bleed through to the other side (and feather a bit).
So I tried their side wire-bound sketchbooks that have thicker paper. The paper was a bit too thick, but whatever works... The thing is, I hate writing into the wire biding, so I'd write till the end, flip it over. A completed volume would have a set of pages "going" and a set "coming" like this:

Then I found some Lalo cahiers at Vickery.com and tried them out. The big one (8.25 x 11.5) was perfect! The paper, an off-white laid that loved fountain pen inks and nibs! I decided to order another, but the large journals have apparently been discontinued!
I tried Renaissance Art -- expensive, even without the leather -- but didn't like the paper. Too thick and too bumpy -- like watercolor art paper or something.
After searching the web, I found that Exacompta makes what they call "Basics" series of journals and sketchbooks. They're called "sketchbooks" if they have unruled paper. I thought I'd try one out, but after emailing a bunch of internet shops, I couldn't find one that either stocked it, or were willing to special order it for me.
Except for SwisherPens.com. Swisher's Jennie Lee told me that If I didn't mind ordering them in packs of three, and be willing to wait a little longer than usual (special order), they would put an order in for this finicky guy. Each sketchbook is 50 sheets, 100 pages long, and the edges are gilt in gold. I can do without the gilding, especially when I calculate that it's just driving the price of each journal up. After all, it's the paper that I'm after.
They look plain straight on...

... but have a shiny, gold gilding (that I'm sorry I don't have a photo of).
The big surprise was that although at 8.25 X 10.5 inches it was slightly smaller than the Lalo cahier, the paper was exactly the same! Yeah! Here's a pic of an Exacompta Basics sketchbook lying on top of the Lalo cahier. For scale, that's a Pelikan 605:

The paper is wonderfully fountain pen friendly. One caveat: its luscious off-white pages are a "laid" paper and have a finely lined pattern on one side (and a smooth one on the other side). Some of us like paper that's smooth as glass, paper like Clairefontaine or HP Premium. The laid side of this paper has a texture (I hesitate to describe it as "tooth").
Here's a close scan of my smallish writing. The "m" in "proclamation" is about 2mm high, and the nib is a .5mm Binder cursive italic (with my own bulletproof Noodler mix, New Old Bishop Street Blue-Black):

I use a very light touch, so the slight texture caused by the laid pattern is a non-issue for me, but just mentioning it as something that might tint some opinions.
Although I appreciate Clairefontaine's (and HP Premium's) smooth surface, one thing I don't like is the way it seems to "absorb" the ink. I'm not talking about feathering, but something else. It tends to make the inks I use less lively. The paper in the Exacompta journal is more like Crane's stationery -- the ink seems to sit on top of the paper. Here's a closer cropping of the above:

No feathering at all, no bleed,shadowing, or print-through!
I don't know if my quest for the perfect journal is completely concluded -- I'm open to suggestion -- but I'm willing to rest at this oasis for a while.
Doug
P.S. Jennie Lee of Swisher Pens emailed me to say that they will be stocking this item -- it's no longer a special order, and you can order them one at a time instead of a pack of three. I can't find the item on Swisher's Exacompta page, but if you're interested, here it is on the "purchase" page.