If you ending up wanting BRISLANDS cylinders I can get in touch with him.  He did shut down the business and couple years ago, but I am pretty sure he still has stock on his cylinders and rebuild kits for them.  Yes they are fully rebuildable and they are made from steel, not aluminum.  They do take a bit more pressure to lift, but they will never break, and being as they are rebuildable  they will last forever. just email me or call me 604-613-6441 or
evolwheels@gmail.com