Otherwise, accepting a BIP32 extended public key from users would be great. God knows how long away that will be. Or even, clients issuing BIP32 keys to anticipate the need for recurring transactions/pubkeys between people, and for better support for multisig. I'd love a QR scan/bitcoin URI for pairing/signing a multisignature address, it's something I'll be working on after a mountain of other work.
Why not give the option to use BIP32 extended keys? Not supporting them because of perceived lack of support from other tools just propagates the problem of no support. I use a BIP32 chain for
getting payments, even though it means that my 'wallet' is mainly a bunch of shell scripts. Because you only need to get the private key when crafting spend tx, private key management is simple because you can just store one encrypted file with your extended private key, and ask for it when needed.
Also, there is support for using bip32 to do multi-signature work in my new program, pymultisigtools --
https://github.com/Zah6ooheew/pymultisigtools -- which will see a new release shortly after I figure out a user interface for signing multiple transactions at once.