Hi Reynold!
Another great option is Spently. Currently Spently gives you a way to customize your Shopify notification emails, but we are moving into exactly what you are looking for. I'd love to have a chat with you, off of the forum, to learn more about what you are looking for. It's people like you that help shape our product.
Send me an email at nicholas@spentlyhq.com if your interested in having a quick chat.
P.S We plan on being very affordable :)