Does Electrum even use SPV? I've read contradictory reports about that.
Not exactly. It does include verifying transaction inclusion via merkle proofs, which is the essence of SPV but it doesn't work the exact same way as described in the white paper.
Multibit is somewhat closer, and is also open source and could be forked, but most alts seem to stick with Electrum.
In point of fact there are NO pure SPV wallets because SPV as described in the white paper also includes the network having a warning system against attacks, which doesn't exist, and the original description doesn't include any practical or privacy-preserving method for querying your transactions either.