RapidFont helps you design OpenType fonts, icon fonts and color fonts directly in Sketch, launching soon! Check out http://rapidfont.com to join the Beta list.
Love this concept! Can I use it to replace Glyphs?
Yes, you can. After you have created responsive shape for each glyph, use RapidFont to export your .otf (or other webfont format) file with one click. This app won't add any additional process into your current workflow.