Not a bad idea.
However, Arch Linux is a very unstable platform for building SL Viewers. Things break all the time, most often than not due to upstream bugs.
I'm in favor of this, with the caveat that up to date builds are not garanteed.
For the sake of completion: Alchemy is now available under alchemy-viewer and alchemy-next-viewer as source builds. Binary snapshots are being considered and investigated.