Possible, certainly. The distances are arbitrary, bounded only by the max size of an int (2^31 - 1 since Freelancer ints are signed) in "m". (Then again, you can also go out to -(2^31) since positions can be negative, so I guess you get the full 2^32 ~ 4 billion m range.)
There's a bunch of tutorials on system modding, this is fairly basic stuff (but still finicky because FL is finicky, of course). I'm not sure who else has the time to do it (I certainly don't) but if you can sell the concept- and it looks like you've a decently worked out plan- you might be able to find some others to help out.