Shop I worked at had a solution for a batch of frames wit similar BB. A steel sleeve with OD 45 mm and ID 40 (which you may have to have cuctom machined) was pressed in simply using a big vice. Then a much more common 40 mm press fit BB could be installed, although 145 mm spindle length is long. I believe 136 is the maximum with these BB's (but they are cheap)

Example:Startpagina / Fietsonderdelen Stadsfiets / Trapas / Trapas compleet / Thun Trapas Spieloos 136/40mm Thompson Inslag