Hey Dale,
If the dealers don't let you audition the speakers prior to purchase then I would be very wary of purchasing those speakers... 'Cos to me, there is NOTHING like a "flat frequency response"... it is all very subjective to every individual's hearing.
I suggest you do some research by going unto the manufacturer's website and finding out who the distributors are for the products you want to audition. Then, contact the manufacturer and ask them to point you in the right direction for a demo. I know for a fact that the distributors for Genelec (Team 108), ADAM & Mackie (ProAktiv), M-Audio (Sinamex) do have spaces where you could go an audition the speakers. You may want to start there...
Best of luck!