We haven't even colonized the moon outside of sci-fi so it's a bit
premature to view Sedna as some kind of development property
Probably will be visited by robot probes within 30 years.

I'd bet it's sooner than that. The New Horizons mission that's scheduled to
blast off for Pluto in 2006 is also designed to visit Kuiper belt objects.
Depending on where Sedna is, it would seem like this would be a logical next
stop on this long mission.