Short answer : no
Complicated answer : good luck with that 
There are a lot of things both in the python core and in the apps which depends on Debian (apt-get, config files location and format, and so on ā¦).
The purpose of YunoHost is to be able to have a server that just works (and kinda hackable). Personnally I donāt see any motivation in being able to run it on Archlinux instead of Debian (though iām not particularly a Debian fanboy). I canāt think of any ākiller featureā that Archlinux have and Debian doesnāt that would really make self-hosting easierā¦
There was a similar project for self-hosting running with Arch called ArkOs, but recently died due to lack of contributors 