i did mean the sbg ones, i must have missed them, probably due to tiredness, on my last read through. my apologies.Oh, whoops. I think I actually only included the ones for having a mobile stronghold since they are better than stationary stronghold benefits. And me without my books. *sigh*
well, technically, the mobility option on a stronghold does not affect the consideration as to whether an item is created with the "bulky but still technically mobile" cost or the "immobile" cost. if it is a permanent part of the stronghold's structure and cannot be removed from said stronghold without destroying it, then it is "immobile". (or maybe i just misunderstood what you meant. ^^ )
for example, i just finished crafting a folding boat as a mobile stronghold. due to the flexibility of the exact size and shape of a stronghold space (p.9 iirc), a folding boat (pinnace form) is still just within one strong hold space. enchant it with mord's capable caravel and you have an auto pilot, servants, sailors, and a fancy extradimensional space you can put other stronghold spaces in - and not have to pay for mobility on them.... on the higher level version, i added another casting of mord's mag mansion, and between the two i have crew space, cargo space, and pc space.
i added the predict weather and detect ship abilities, ie: radar. with the self-motility, submersible, burrowing, and flying option, even without wind it can move at 10mph in land, air, or sea. i also paid for some extra masts with sails for flying mode - mostly because it makes sense... and looks cooler. the protective enhancements work on anyone inside or on deck, it is made of livewood so it can self heal, it has nystul's on it to hide the magical effects, the hull is transparent (painted over to leave portholes), the space is fireproofed, and most of the enhancements work even in rowboat form, which is somewhat amusing (i can even pull a CJS at the pier to avoid paying the docking tax... ^^ ) . and it all folds up into a box when i need to walk away with it sneakily or not reveal my arrival/departure for some reason. as an added bonus, i can cast dispel magic on it to suppress its abilities during portal passages and the like.
i'm thinking my next enhancement will be the higher level terrain spell (phantasmal terrain? the one that lets you hide structures) on my boat... ie: cloaking shield. make it look like a cloud when flying, or a wave when sailing, or like a stream of water or lava when submerged or burrowing, respectively. won't hide the people, but they can't be on deck when submerged or burrowing, anyway. =D