Now that newer designs (this is more for my wife, as I prefer backpacks) have single-arm pull designs, what are people doing now to balance their shoulder bags/purses what-not on their rolling suitcases/bags?

I remember having this problem before and swearing off rolling bags entirely (because they are more hassle, to me, than they're worth in extra weight). You put a shoulder bag on the bag, with a strap in hopes it will stay put, and it swings out under the arm. Hooray.

Is there a contraption that's reliable/cheap/lightweight that could say stabilize a shoulder bag? Am I the only person who's encountered this?

Thanks.