quick update on this: I just got all the materials in the mail today (that was quick). Basically, bad idea. The 2 covers arent even leather, they're like a thick cardboard. Shows what a noobie I am at arts and crafts. :-D
That said, it does *look* good, its sort of 'embossed' (stamped with a pattern), and with the very nice scrap leather brown strips I got, it would "look" nice. However nothing is going to beat a real leatherette cover obviously. ANd now that I know the normal sony cover fits well after all, I'll probably stick with that.
I'll probably go ahead and glue a leather binding to these two cardboard pieces just for grins and i'll post a pic. It does look nice, even tho soon as you pick it up you know its cardboard and not leather
That said, the underlying idea here is sound -- if you can find an old leather 5x7 journal cover, it should make a fine and nifty cover for the reader. Problem is it may not be as inexpensive as I first imagined