We've dealt with Paul Lavoie (
http://www.paullavoieinteriordesign.com/), which has been great.
A couple other top calgary designers are Corea Sortopa design or Douglas Crickland.
If you are dealing with someone that is good at what they do, you tell them what you like and would like to see, and they will put it together.
And the reason most show homes look the same, is because most home builders take on a very safe approach to design in order to appeal to the greatest range of audience.