Speakers that have wide horizontal dispersion

The Totem Model 1 sounds great all over the room, as do many of their other models. Used, they would fit your budget.

I always thought my dunlavy sc3's did a good job;I would think sc4's or sc5's would even be better.

Indeed the dispersion plot of the Revels does look good. To be fair their are quite a lot of options for speakers with good dispersion without having to resort to Beolab 5's other omni type designs...

Where is Duke when he is needed?

Try experimenting with your existing speakers. If you go with extreme toe-in, you can effectively improve coverage. If the left speaker is aimed at the viewer/listener on the extreme right side, that listener will get a loud signal from the left speaker and will be off-axis from the right hand speaker (because that speaker will also be toed-in) -- this will provide some compensation for the difference in distance between the listener and the two speakers.

Back in the 1970s, the Leslie company (yes, the organ people) designed a speaker with limited dispersion for specifically this purpose. The limited dispersion reduced the amount of signal off axis, to have the compensating effect I have described above.