You don't have to wait for NXT Multigateway (MGW). The dev James released Universal Multigateway (uMGW) as he won't have the resources to support all coins and pairs that come along, the communities can do it for themselves.

MGW allows NXT/Other coin
uMGW allows NEM/other coin. Then you can trade NEM/BTC or NEM/DOGE, as many pairs as the community wants to add.

I don't think you can do NEMstake/BTC, NEMstake/DOGE .... Not yet at least but James is planning asset to asset trading (NEMstake/jl777hodl for example) so I imagine this will still support NEMstake/crypto.

But multisig needs to be supported first.