Electrum.. wouldn't trust my main stack to be held by an Electrum wallet (too paranoid about the seed being derived somehow)
What's wrong with Electrum? I think you are very flexible with Electrum. You could use Electrum with 2 of 2 multisig (one seed on an online computer and another seed on an offline computer). You use the online wallet to watch your balance and to generate the transactions (including the first signature) then the offline wallet for the second signature and then again the online wallet to broadcast the transaction. You can do this very easily with Electrum. Or you could use 2 of 2 multisig with Electrum and a hardware wallet (one seed from Electrum and one seed from the hardware wallet). Or even 3 of 3 multisig with one Electrum online seed, one electrum offline seed and one hardware wallet seed.
Besides, Electrum is the first and currently only wallet that supports native segwit (bech32 addresses that start with bc1...).