I'd think any of the SET tube guys speakers would be up your ally. I've tried and liked the above mentioned Omega SAM's, I own and love the Living Voice Avatar 2's (look further up the chain if your budget allows wonderfully musical speakers, also note UK pound makes these a much better buy right now), Tekton, Zu audio and Horns are a few others from the top of my head. Try searching high efficiency speakers here, there are quite a few good threads.
I run a SET 8wpc amp so I'm familiar with your issue and its not backwards you just need to focus on higher efficiency speakers above 94db, depending on your listening volumes maybe 98db if you like it really loud.
I run a SET 8wpc amp so I'm familiar with your issue and its not backwards you just need to focus on higher efficiency speakers above 94db, depending on your listening volumes maybe 98db if you like it really loud.