Unfortunately, the W3C and the browser vendors are inching towards a depreciation of SVG fonts — each citing each other's unwillingness to support the format (Google search).
This makes Truetype (TTF) the only supported alternative. The newer formats WOFF and OpenType are just container formats that sit on top of TTF. Unfortunately, TTF is a binary font format that requires dealing with search indexes, binary flags, and memory management. Consequently, it is impossible to write such a file by hand. Furthermore, TTF is operating system dependent and behaves slightly differently across different operating systems.
Personally, I find it sad and irresponsible to give up a declarative and clean font format for an ancient, binary, and system-dependent font format. However, since this is the decision, so be it. Here is an attempt at a Java program that converts SVG font files to Truetype font files.
The converter is experimental code. It understands only a very limited set of SVG font files — most notably those produced by PowerLine. If you wish to do anything else with it, you have to mess with the code!