My memory is a little fuzzy here so please bear with me if I give misinformation.
The Escom 4000T and the C= 4000T are essentially the same parts internally, at least early on. My Escom 4000T had some C= branded parts, I just don't remember which specific ones. I do know the Escom 4000T case was an AT case made by Enlight. I found extra drive rails at one of my local pc shops. The power supply likewise, just a standard "AT" type.