I've spent the past month and a half perusing travel desks, writing boxes and writing slopes online. Ended up buying the one Hana linked to after missing bidding on one I was in love with on Ebay (am still kicking myself). I'd recommend searching ebay with the terms "writing box", "writing slope", "lap desk" and perhaps "stationery box" if you're after a genuine antique. There are about three pages of them up right now. I know because I'm compulsively checking every day.
As for the one I bought, it's perfect for what I needed it for--something to take with me in the car when I'm waiting on one of our daughters after school. I like it a very great deal now, but I will admit to being a little disappointed when it arrived. The finish wasn't as well done as it should have been (very visible fingerprints in it on the front, stain was put on a bit sloppily in places over the metal hinges, latch and ring on the drawer, and it was sticky with wax, although the stickiness has worn off, and as I said, I'm loving it now despite its flaws). Sturdy, though, I'll
certainly give it that, and I'm a sucker for all the little compartments, for sure.