Thanks to you both for your help, though for some reason I can't see the image for which you provided a link. Gives me a 400 error.
Just so we're clear, it's a full-size rollaboard, so there's no way it'll fit under a regular seat. But if the bins are standard size, it'll easily fit into the bin wheels-first.
The weight limit just seems silly. Widely-ignored rules like that irk me.
