I don't think you're missing anything, I have never found any high level missions in Liberty/Bretonia. You have to get to Rheinland for level 30+ missions. I don't know how high the missions go in the border worlds... Currently the Corsairs hate me so I've been staying in the nice safe known parts of the galaxy...

Now remember[! First you pillage and THEN you burn[!

I've found missions that are as high as 20 or 25 in liberty, but they are few and far between....yeah, the progression in difficulty from easiest to hardest should work out like this... Liberty, Bretonia, Kusari, Rhineland, then the Border Worlds...

The highest missions that I've been able to find are lvl 39 on the Planet Crete. This is, as far as I know, the only place that offers high end missions.

As a side note, the lvl 39 missions pay about 140K. I read on a post somewhere, don't remember where, that it is possible to find 250K missions on Crete. Just wanted to know if it was at all possible?

but what would it take to finish one of those ultra hardcore missions?

I'm on lv30 with a Sabre and mostly lv8 weapons and shields

Yeah I saw a post touting 250k missions too, but I think he said they were for the Outcasts. Not sure now. But I know I've never seen any that high.