In your position I would go for HaBe/Hu/Ar/As of Trog. Trog is a great god for stabbers, especially for halflings who have broad physical skills (in your case Slings, Fighting, Short Blades, Dodging, Stabbing, Stealth), Berserk greatly increases short blade damage output and Brothers in Arms handles everything else. Plus, he is a strong god to use with Evocations: ?acquirement offers rods which allow you to use great spells such as Freezing/Poisonous Cloud, Poison Arrow, Summon Swarm, Abjuration, Summon Demon, Deflect Missiles.
Finding rods is rather luck-dependent, but ?acquirement helps out here. Trog caters well for everything else, and rods are definitely not a must for this build - but they are good and if you want artificing, go ahead.
Especially since Slings and Throwing crosstrain to make them +8
or +7 respectively, I'd possibly pick up some of that to augment my stabbing (needles of paralysis/sleeping/confusion). With your Evocations skill, evokable invisibility will be a boon too, and useful right up to and including Zot.
Elemental magic, slings and melee/stabbing sounds like a harder build to actually be strong and both an elemental skill and physical ranged is sort of weird; I'd probably pick HaIE of Okawaru or something but the build described above is stronger, easier and, in my subjective opinion, more fun.
Hope this helps, good luck.