I'm not a fan of blowing for a long time anyways ; )
NAPA on Ellice has a reference book and decent selection of plastic fasteners, if you bring one in they should be able to find a match. Bring a caliper just in case for taking measurements.You could also go to the dealer if you want to spend $$$.
How many do you need Colin? I could possibly grab you some from my work or even something similar that will work.
I have a eBay bag of them. I'll check how many left when I get home. Cheapest source. 6$ for 50.
This is what you want to buy to help remove them...I love these toolshttp://www.amazon.com/Popper-Window-Molding-Upholstery-Removal/dp/B00JX47EU8
Does this remove them without mangling them to pieces like my flat heads do? I wonder if these are available locally.