Garthanos
Arcadian Knight
The Advanced Player's Guide from ERP has a set of crafting rules which includes both building things and creating art. It works somewhat like Rituals - you pay a cost in time and money to learn how to make the craft, and then when you want to actually create an object you roll on the related skill. (For art it's Insight; for smithing it's Endurance.) There are rules for how much the kits to create these items cost and what the DC to create them is.
As for singing, in my game I added 3 skills: Perform (Cha; covering singing, dancing, making speeches, etc), Natural Philosophy (Int; because I wanted a non-magical academic type skill) and Tactics (Wis; mainly for symmetry, but also I like the idea of warriors having a knowledge type skill so they're not all muscle). Then I gave most classes an extra skill choice and made these class skills for some of them, so that players aren't penalized by having the same number of choices spread out over more skills.
I don't know how well this works since none of these skills have actually come up yet. Heh.
Heh, love it.. I like how this thread has brought up some very nice roleplaying ideas, those skills have very flavorful elements to them which invoke something like ancient greece.