I've got an Air America Apocalypse system that fits fine on a bottle made in 2001. I think there's a 99% chance you can take off those Armageddon regs and install them onto a new bottle made this year.
You can buy new 4500psi bottles through Crossfire's website
. Alternatively, you could scour the BST on this site for people selling used bottles as well.
And you might need some parts like o-rings or seals to make sure the reg is working properly. Try getting this parts kit
off of iisports and you should be good for a few years.