Ultima VIII - Exile, which began in mid-2002, was one of the most ambitious remakes. Corvwyn, the leader, aimed to remake Ultima 8 using the Neverwinter Nights engine, recreating the original Ultima 8 atmosphere with enhanced graphics, much better dialogue, an enhanced plot with corrected inconsistencies, and even additional side quests. The team was even considering creating The Lost Vale in the remake, once finished. I was the lead dialogue writer for the Exile team, and I also had given a hand with quests, and I was the one who came up with the name. Unfortunately, the project was cancelled in 2006.
With permission from Corvwyn, I am hosting some surviving media from Ultima VIII - Exile.
Another Ultima VIII remake for Neverwinter Nights was being developed by The Red Mage. After releasing a demo of his mod in August 2004, he cancelled the project after discovering the existence of the Exile project. After Exile was officially cancelled in 2006, Ultima 8 for NWN made a brief comeback in September 2006 with a new demo.
The files that used to be at the project's NWVault page (Internet Archive) are gone, and the project's website was lost with the demise of Geocities. Although Aiera (which is now The Ultima Codex) had salvaged at least one of the demos (if not both), neither seem to be available at this time.
Additionally, Ultima: The Reconstruction's entry about this project has a very small screenshot, a demo download link that seems to be corrupt, and some additional information.
A third remake of Ultima 8 for Neverwinter Nights was started in 2010 by koden-km. On 20th March 2014, he uploaded the project to Github so that others could see it or even continue the project if they wish.
From the Github project page: An old attempt at remaking Ultima 8 Pagan with the Neverwinter Nights toolkit.
I last worked on this some time in 2010. I only used the built in tilesets and assets that were available. I can't remember if it needed the expansion packs. Most of the map entries/exits should be connected to walk through the world. I don't think any of the houses in towns have indoor areas yet. I don't think i had any NPC's or mobs in there yet.