What a nice little build, you have surely piqued my interest.
So on with the barrage 
- What are the specs of the PC you use to run this?
- The sides look like 18mm (or 3/4"), what material thickness are you using for the rest?
- Were you so lucky that the visible width of the backglass monitor was exactly visible playfield monitor height plus 2 x material thickness?
- How is the painted lockdown bar handling sweaty palms?
- Do you have any internal pics?
Hi Sho,
Sorry for the very late answers  

 I was very busy with building a kitchen en painting doors and all kind of crap you came across when a son buys a home  
 What are the specs of the PC you use to run this?
 What are the specs of the PC you use to run this? : AMD A8-6600K 3.90GHz FM2, Asus PCI-e Radeon HD6670 1GB, Crucial 1x8GB, DDR3, PC12800, CLI9, Ballistix Sport, Gigabyte GA-F2A88XM-HD3 AMD A88X, SAT600 RAID, Seagate Harddrive 3,5" 1TB, Sata600, 7200rpm
The sides look like 18mm (or 3/4"), what material thickness are you using for the rest? : All my build I use for the sides 18mm and the rest is 12mm MDF.  Works for me  
 Were you so lucky that the visible width of the backglass monitor was exactly visible playfield monitor height plus 2 x material thickness?
Were you so lucky that the visible width of the backglass monitor was exactly visible playfield monitor height plus 2 x material thickness? : No, that was no luck, there was a lot of planning and lurking for the right monitor. Fist I had a 15"backglass monitor, but that was to small for a non bezel frame, so replace it for a 17 and the playfield 24". And after that I could made the slots for the side panels to create the none bezel look.
It feels better to have a non bezel look for this, otherwise the whole thing became a lot bigger and you got large aluminium L strip to cover the monitor frame, and that's what I don't like  
 How is the painted lockdown bar handling sweaty palms?
How is the painted lockdown bar handling sweaty palms? : For now it still holds  

 There is a lot of primer, filler and paint on it, so it HAVE to stay good  
 Do you have any internal pics?
Do you have any internal pics? : Not for now 

 but if you want some special screens, I could make some if I find some time for it.
Greetings  
