Hey! First of all, huge thanks to the author SilentResident for the amazing work on the creation of the ImpeREAL Castles for Oblivion. I have converted her ImpeREAL Bravil Castle to Skyblivion and she has granted me the right to release it (and any other of her castles).
It's just a 15kb esp but it has taken a lot of time to get it converted. Maybe I'll get all of her castles converted with time, so I'll be updating this post with new castles' esps. This mod will probably become obsolete when someone happens to convert Better Cities, or it can be merged to the Better Cities converted mod to save time. Either way, it will be fun to have these castles in Skyblivion for the time being.
The only problem I have faced so far is that the Bravil castle is not being properly viewed from distance in Tamriel worldspace. You either have to come out of the city to see it right away outside, or get close to the city walls to start seeing the castle. Skyblivion LOD resources are yet to be included (thanks for letting me know zilav!).
(Edit) I've finally finished converting all of the castles. It took some time but it was worth it. I've uploaded a merged version with all the castles so there's no need to have an esp for each castle in the load order, unless there's any that you don't want, in this case you can still download them individually. There's also a patch for Skingrad made by pimpskinny which contains a few meshes for LOD, so I'll be trying to get them converted to Skyblivion. If it happens, I'll update the Skingrad Castle's and the merged Castles' archives. I hope it brings more immersion to your game as it has brought to mine!