The source for an interpreter for FFE (frontier first encounters) can be found - maybe -
here; at least, that's the official page.
This is a mirror of that page, though how recent it is, I don't know; the original one doesn't load for me.
I had a look at it though, and whilst the guy claims it has a working SDL port (which theoretically ought to be fairly straight forware as a port, at least to those who are fairly good at it), it also has a couple of decompiled ASM files ammounting to about 2 megs of code or so. Whether or not these are actually used, I haven't a clue - but somehow I suspect they may be (I haven't a clue how to find out). If not, then it ought to be SDL, and therefore straight forward. If yes, then it would be a mammoth project and require someone who knew a LOT about assemby (bearing in mind its reverse enginered anyway).
I haven't heard of the source for Frontier Elite 2 being out. Tried it on Castaway a while back, but to be honest, I found it too slow. Which is a pain, but there we go...
Maybe if Skeezix implements Cyclone, once its finished, it (and a few other 3D games) might run slightly better - that would be oh so nice
.