Hi Alex,
Im currently working with Karry from OSM to establish a replacement for the missing hillshading tiles. See here: https://www.openstreetmap.org/user/Karry/diary/47416
Its not production ready yet, because i have to implement some rendering/caching to not overload Karrys servers.
Will update you on this when its ready. Do you think this will help? Its already working in my dev environment as simple replacement in hillshading.dgml
best regards,
Andre