Good morning,
I propose the Asus Zenpad 10 (Z300CG) 
Without really knowing it, but I predict: no chance on a customROM.
The elegant looking tablet from 2015 works only with the network standard 2G (EDGE/GSM) and class 3G (WCDMA) and of course WLAN802.11 b/g/n.
Surfing at home without LTE via WLAN would be okay. But for an Intel® Atom™ CPU there is probably no custom ROM maintainer …