Those are moderately popular with the FJ80 crowd. Here's a DIY. Its for an 80 but you get the idea.
Gull wing windows. You may even find a DIY for yours out there. The hard part is the hinges, the rest you could draw up and have a company cut the pieces out for you. Probably $50 plus the aluminum to cut it.
The ones I've seen for sale run about that price range and up. Looking at the one you linked, the weatherstriping apears to be genaric from an industrial part supplier, hinge I couldn't tell. That means if the company goes out of business you should be able to piece parts for it. If the door is set properly that design shouldn't leak. I would have prefered a channel to push water away or at least something up top to do the same. That's something you could actually make by gluing another rubber strip just under the top if needed. Either way, that design looks to hold up unless you power wash it right at the door.
Most of these companies sprung up in the last few years filling a niche market. I know for my 80, there's only one out of four that still makes/supports the gull wings. It would be nice if worse case you could put it back if something broke and the company is gone.
One thing I have seen mentioned on your body style is the actual size of the opening. The glass is considerably larger than the hole. On one of my forums, a vender was gauging interest in your body style. The opening size and was a concern for reaching into a cooler. In your link it looks like the company installed a cabinet behind the door. While that would change things, you now lost inside room.
Over all, I keep thinking I may put them on my 80 but can't seem to justify it.
