Sorry for my late reply, but I’ve decided to make a custom_component, which does the job.
If anybody is interested I’ve uploaded it to github: https://github.com/nvanggaard/clockalarm
It is maybe not the most pretty code, but it works
This alarm works great paired with Bob_NL’s Chromecast Audio “Residence Radio” project (released Feb '17). Sorry to revive this old thread, but just wanted to link the two to eachother.
If you want this alarm to run scripts rather than scenes, you can change its python script line 43 and 45 from “homeassistant” to “script”.