Most of my arranger keyboard type gigs are solo acts but I personally like (even MORE) playing with a solo acoustic instrumentalist (horn player, guitar player) or female vocalist (if the client can afford this).
The BIG advantage we have as arranger keyboard musicians is that we have the flexibility to add/drop LIVE musicians (drummer, bass player, instrumentalist, etc) as dictated by client budget or musician availability.
I think an arranger keyboard duo act is probably my favorite gig scenerio because no matter how you cut it solo, there really is NO substitute for the exciting musical chemistry which can happen between LIVE musicians/singers performing on stage. Also, I'm sure that most of the males in the audience appreciate having a lovely female singer to admire as well.