I've been spoiled by smithing. Now that my new character doesn't have it, I'm finding myself a little crippled... Where is, uh... Where can I find glass weapons, armor, etc? Dungeon diving? Shops?

Once you hit a certain level it will become possible loot, I think.

At about level 30, maybe a little lower, I started seeing tons of glass weapons in dungeons but no armor.

http://www.uesp.net/wiki/Skyrim:Armor

Most items are randomly spawned from loot tables based on the player's level. The following table describes the standard level at which an armor type begins to show up randomly for the player; lower level armor will also randomly appear. Enchanted versions of each armor type will begin to appear one level later;
Light Armor
1- Fur/Hide/Studded
8 - Leather/Studded Imperial
12 - Elven
19 - Scaled
27 - Elven Gilded
36 - Glass
46 - Dragonscale
Heavy Armor
1 - Iron/Banded Iron
6 - Steel
12 - Dwarven
18 - Steel Plate
25 - Orcish
32 - Ebony
40 - Dragonplate
48 - Daedric

Higher tiers of weapons and armors will start appearing on merchants and in chests as you level. Glass / Ebony usually starts around level 30-40. There are other sources before the level threshold, though. For example, Draugr Deathlords will very often carry Ebony weapons regardless of the player's level. Thalmor patrols are always wearing Elven armor, and pretty often, elven and glass weapons. Glass armor... might be trickier to find.