The other option is MOSFETs. They can handle huge loads without wasting too much power as heat, so I only need one per motor coil. You seem to have to buy them a singles - there aren't any cheap 7 or 8 way packages. They cost around
I am definitely satisfied that the SN754410 or L293N is the way to go. Until I change my mind again, anyway.
Edit: Turns out the SN754410 is only 1A per channel (2A per device). The L293D is 1.2A per channel. I will need the full-fat L293N, rated to 2A per channel.