You've gotten some good recommendations for matte papers already, but I'm not sure I understand why you're looking to matte papers as an alternative to EEF in the first place. When you say...
I really like the colors coming from the Exhibition Fiber but was wondering if there is an Epson matte paper out there that might have a better print permanence while retaining the extraordinary color characteristic of the Exhibition Fiber.
it seems that your concern with EEF is permanence; but that's not a matte-black versus photo-black issue. There's nothing inherently more permanent about matte papers compared to fiber-gloss/baryta. So if this is just about permanence and OBA's, I'm not sure why you're looking at matte papers since you're so happy with the color gamut of EEF. The truth is, no matte paper is going to make you happy if you're looking to match the extraordinary colors of EEF. The top fiber-gloss/baryta papers such as EEF and others have color gamuts close to double the volume of even the best matte papers, not to mention the night and day different in DMax.
That's not to say matte papers can't be nice. They have a unique look that many people like (thought a good bit of that gets lost once you put them behind glass, IMO). For certain images matte papers can work really well. But if you like the look of your EEF prints, you may not be happy with any matte paper.
There are plenty of other, more permanent fiber-gloss alternatives to EEF. A few OBA-free options that come immediately to mind are Hahn Photo Rag Baryta, Canson Inifinity Platine Fiber-Rag, and Crane Museo Silver Rag among others.