fbsp comes from qfusion, and is really just rbsp (from raven's q3-based games) with bigger internal lightmaps (which is quite minor in the grand scheme of things).
to implement it, you first need q3bsp and all of its capabilities. you then need to implement multiple lightmaps per surface, and blend them together, probably while also trying to deal with q3 shaders...
which is probably why dp doesn't support it despite already having q3bsp support.
so yeah, fte is the only q1 engine that supports it, and dp can only be described as inactive, so I doubt that's going to change any time soon.
when GB was messing around with rbsp, he found q3map2's support for it to be somewhat dodgy, resulting in various lighting bugs. So watch out for those. Maybe they've been fixed since.
mh was messing around in rmqe with a lighting system like that imposed by rbsp (there are performance advantages when your entire [highly detailed] map has smoothly animating lightstyles), but that engine lacks all the other things q3bsp would require.