I was gonna say this exact thing. The dimensions on the Oskars are pretty much perfect for video game display and they hold a ton of games. I actually ordered a few Oskars but canceled because of all the bad reviews regarding quality of the components. I then looked more closely at Billy Bookcases and realized there is no better value or quality for mass market shelving. The big Oskar is $110 while a large white Billy is $49! Alternatively, you can experiment with more unusual shelving setups like I did earlier in this thread with things like the Furrino organizers. There are a lot of fun things you can do with shelves that weren't meant for games if you're willing to a little customization.
In the end, custom is clearly the best in terms of usability, but it's a lot of work, can still be costly, and may actually hurt the value of your home. If you do go that route, there are thousands of YouTube videos to get you started though.
My suggestion? Order one of the smallest type of shelf you're considering and see how you like it. Then either switch to another brand or buy more of the biggest size available. Good luck!