I use arch for months and I'm just discovering how powerfull this distribution is !
Fisrt take a look to the ABS system to make packages from sources ! With this system, I've been able to build the brand new version of banshee (which is outdated in arch repos). I've also used this method to build the last "experimental" version of monodevelop.
Note that if you build a newer version than the repos' version :
- 1 use pacman -U /path/to/my/brandnewpackage (u means upgrade)
- 2 expect warning messages fo further `pacman -Syu` you will do.