Apparently it can house up to 107HP
https://waldorfmusic.com/en/kb37
To get this width you would need to buy 1m rails and cut them to measure. Otherwise, you can get a Make Noise powered skiff and fit a spacers on the sides and have a bit more than the nominal 104HP.
Otherwise, if the keyboard is a must for your requirements, look at the WMD Monolith.
Apparently, submission for new modules seems to be limited to 104 HP, which is the usual maximum width for racks most mortals have. However the case/utility collection below exceeds that, going up to 120 HP:
http://monome.org/isms/
hang on a second, wasn't Serge supposed to be an affordable DYI option back in the day??
The currency for module prices seems to default automagically to USD, despite having EUR set on the user profile.
This happens quite erratically, without any particular defined pattern. Not a big thing, but you know...
Keep up the amazing work Knut!
Grüße!
