What features are you looking for?
Bumping this thread because I like Armory's fragmented backup, but I just cannot devote 80 Gb of disk for blockchain + Armory cache. I tried Electrum's multisig, but I don't understand it: I need to add other signers' master key.
Most, if not all, SPV wallets are based on seeds... You can fragment that seed. As for fragment security I'm not sure what would be possible to do. Maybe hash the seed? Or maybe scramble the words.