New version of ETS2 1.58 just released couple days ago but we already have some news from map modding community. It is still not time for gigantic map combos but if you wished to start 1.58 story with additional map you can do the switch. Below I provide only several mods with links and some upcoming updates.

Roextended 5.0 – new Roex map available in free and premium edition and going further in Poland – new cities Rzeszów, Przemyśl, Sanok, Krosno. Extended connections in the area. Fixed all reported bugs and updated materials to 1.58.
Roex road connections – currently available updated RCs to rusmap and SR Map but soon it will be added other connections when those mods release.
rusmap 2.58 – Adaptation for 1.58 without new content. Fixed errors found in previous version.
Sibir 2.12 – both paid and free versions announced on the live stream and will be available this weekend.
Promods 2.81 – announced but without dates and details. Same for Middle East 2.81, The Great Steppe 1.5.1 and Maghreb.

Other mods released:
Oberhavel 1.7.3 (1.58)
SJMap R7 
Trucksmap UK 1.4
West Balkans Path-Breaker’s Direction Map 5.2
Sverige Södra Expansion 1.1.5
Central Bohemia Project v.0.2.4a
Île-de-France (Paris Suburbs) 0.1.6b