Ya like said in the other thread I love this kind of stuff, and looking really good.
If you don't mind another thought I have box scans ( just front and back) of all the US release games, you could work them into your sleeve which would look really slick and almost official, when I get a moment I can mock one up, if you don't mind man?
I don't mind at all.
In fact, if you make the Left or Right black-flaps longer, so it'll cover the entire back side of the envelope,
it would make it easier to get any artwork ya wanna put back there, to line up.
I don't have as much free time as I'd like, so if you want to take this project over, I'm all for that.
IIRC, you even have some equipment in your possession, that would make it easy to churn out a bunch of them.
What kind of card stock are you using?
I used some old cardstock, that I kept in a plastic bin.
I no longer have it's original packaging, that showed the paper's brand and weight.
I'm sure Sparky can pick a nice paper, that would go well with it.