Having a lounge set up can be a great way to engage your delegates in a different way for specific talks. This can be really effective in enclosing the space and creating a more personal atmosphere.
Getting a printed banner could be a great alternative, to make it more adaptable to your brand and vision.
Michael Kors Shanghai
More expensive alternative to using key concepts spread on stage
Relatively affordable design concept. Possibly put lights in side to illuminate words
White cutout option
Light lettering option 1
Greenery in Letters (more expensive)
CSA or Game Changer option Giant letters made from pallets! via style/swoon blog
Using a green Wall behind your stage could add focus and dimension to your space. White writing "game changers" or "CSA Conference".