I don't know why people are recommending a router table for a cross grain housing/dado joint, unless you've got an accurate sled or sliding fence on your router table then it's pretty much the last way I'd go about doing it. As you rightly pointed out it means referencing off the short edge of the workpiece, plus there's every chance the workpiece will dive into the cutter gap in the fixed fence. And even with a sled or sliding fence it's still not plain sailing because it has to be bang on accurate, which in real life isn't as simple as it sounds.
The better way to go about it is to make yourself a simple jig and run a handheld router alongside the jig's fence across the workpiece. Google "Router/Dado" and you'll find lots of plans.
Finally, you mentioned non-American saws aren't set up for dado stacks. That's not strictly true, most aren't but quite a few are.
Good luck!