I have always wanted to play URF in Howling Abiss, full ARAM experience... That must be super fun! Of course games would be like 5 minutes long, but nonetheless all in one lane with ARAM rules... I think it would be super fun. Why haven't you tried it yet? Is it too hard?
You can even make it as a choosing mode for ARURF. Like choosing ARURF in Summoners RIft or Howling Abiss.
PLEASE make it happen someday!!