http://www.pspec.com/
Just ask for Dave and tell him what you want..they aren't listed on the website, but you can get the phone # there. Seems like they had a 7.4 X 8, 7.5 X 8, and 7.4 X 8.25..not a wide selection, these are APC props, just CF props never became legal for Q40 so they didn't develop a very large selection. Funny thing..seems like these prop sizes don't match the ones on the APC website, but I have had all of them....
Some guys are using regular gray APC props like the 8X8, but I like the CF props..again just my personal preference. Sticker shock is $7.50 each.....