The International Association of Coptic Studies commissioned a unicode font which is now available in a stable version called Antinoou. The beta version was known as Keft. I have created a digital keyboard which is free and works well with MS Word. You can download it from my Coptic digital resources webpage. In a few months, I hope to update the keyboard to include Old Nubian characters.
UPDATE: This is apparently the final beta version, and not the final release. A few minor wrinkles remain to be ironed out.