This has already been discussed at length. I think Chris' opinion was that they should be this mind blowingly, insultingly, nigh-inattainbly expensive. They are mostly on the trader's list for the sake of completeness (read, for the lolz)
Ah ok thanks, I missed that conversation... or wasn't active back then=)
Anyways, I think 130M is a bit over the top... one kill per four seconds is really not that much. Superfortress is way better in almost all aspects(all except energy I'd dare say) and it's a bit (what, 15x?) cheaper...
Well, despite the decent threat a Mk. V ion cannon can pose, it is rendered a completely not worth it thanks to the cost. As I mentioned, that was by design.
You know, if the Mk. IV and Mk. V ion cannons are supposed to be a complete joke in terms of cost (and from I can tell, they are supposed to be, and they are even meant to be this overpriced by this insane magnitude), maybe you should remove it from Zenith trader. Right now, and I am serious here, it is an insult for the player to be even offered this effectively worthless option. And as this thread shows, people will continue to complain about it, even if it was stated to be by design.
The Mk. III is VERY pricey too, but feasibly attainable. Therefore, I think it should stay.