Badly needed: Variable Price Items

I've been thinking about your post for a few days now.

Wouldn't it work to have a wedding band be the product. With variants for the additions/amendments?

Rose gold band - product
1. Large diamond, medium diamond, small diamond.
2. Size
3. Etc

Or is it not that straight forward for pricing?
1 year e-commerce, 7 years B&M store.
5 0 5

A variable price item would be a hugely helpful addition to Shopify. As with the original poster, we are a manufacturer who offers both stock items and customized versions of those stock items. All I would really need to make this work is the option to add a variant marked "custom" that would allow me to put in a price manually and add a note to the line item that specifies the customization. This could default to my base price, but be adjustable. I've looked through some of the suggested apps, but they look to rigid to suit my needs. From what I can tell, to use the Bold app without messing up my stock items, I'd have to recreate my entire inventory a second time to offer the custom items. As the stock items are pre-made and the custom are on-demand, I can't show any options on the pre-made items. I realize that the Shopify platform is not meant for this degree of complexity, but this seems like a fairly simple addition to me.