Ok, looks like it'll take more work than I anticipated. Sorry guys! I might still do it though and experiment, it looks like a fun project.
I suppose what i'd need is a
strip of scrap leather (so add another $5 to $10) to make the middle fold, glue it to the two covers. (Or just take it to staples and have them put a spiral bind on it!).
Argh, sorry about that. I totally got mislead by the pics (once at the sony website, and then of these journal covers!). Argh.