You're not alone on this; several customers have suggested it before. I think it's time Koodo paid more attention to this. I'm in agreement, considering their main competition Fido and Virgin offers the higher storage models and all the colour options of the 5C too.
FYI the 5C only has 16 or 32; there is no 64 GB model.
It would be easier if iPhones ever offered expandable memory but alas; they want to add even more money to their mountain of gold.
I normally try to cater to people's phone opinions, but have you ever considered the HTC M8? For the same price as the iPhone 5S 16GB, you get a 32 GB high-end device that offers expandable memory up to 128GB with a fabulous bigger display, awesome front facing speakers, and a wicked metal design. It's a tad on the larger size but you get used to it. Plus it has some tricks like the HTC Zoe app for creating mini slideshows with your photos, the TV app and a built in infrared at the top, and a great interface.
I know a lot of people are loyal to iPhone, but the grass is greener on the other side. :P