Thanks to everyone that chimed in on possible custom frame bags makers here in EU (related thread), ended up ordering the bag from ENA Bags. Super responsive, and gave me the idea that they (well, Ioannis, whom I talked to) were very happy to meet my needs.
The bag has 3 pockets, two on the drive side, and a document pocket on the other side, and internal attachments (pump and key hook). The bottom section is separate and can accommodate the Apidura 1.5 litres bladder (upon my request). There's a small port against the bottom tube that can be used to pass any cable/tube through it.
On top of that the bag is super well done, top quality. Can only recommend.
by The_Peach