I've read about the unique and rare ships at some of the Vendetta fan sites. I haven't yet seen a valkeri for sale anywhere in Itani space, nor have I seen any special corporation vessels.

Do you need to be a certain faction level to even be able to see these ships?

Yes, you need to have a certain level, depending on the ship. Corporate vessels are found only in the corporate areas, and you will need to have a high standing.

+800 or more standing.
Usually level 8 or higher in the respective license.

Which reminds me- does minign license bring any specials? Like a mining hauler with a ton of built-in mining beams... That'd be cool...