There are several Sign Language Orthographies that are designed to be written linearly and have already been implemented in ad hoc fonts.
One of the most important being Stokoe Notation which was brought to Unicode's attention back in 2012:
PDF of paper: Towards a Unicode encoding for Stokoe Notation
There is also a Stokoe inspired system used in Sweden that has a working font and online dictionary:
Teckenskrift – Att skriva teckenspråk [edit: corrected link]
It should also be noted that SignWriting recently received official Unicode support, however it does require quite a manipulation by software to be displayed correctly as it is not meant to be typed/displayed linearly.
There are several Sign Language Orthographies that are designed to be written linearly and have already been implemented in ad hoc fonts.
One of the most important being Stokoe Notation which was brought to Unicode's attention back in 2012:
PDF of paper: Towards a Unicode encoding for Stokoe Notation
There is also a Stokoe inspired system used in Sweden that has a working font and online dictionary:
Teckenskrift – Att skriva teckenspråk [edit: corrected link]
It should also be noted that SignWriting recently received official Unicode support, however it does require quite a manipulation by software to be displayed correctly as it is not meant to be typed/displayed linearly.