source for fenders for 27" tires?
 

Every bike shop I have checked so far (ok only 2 ) is not sure if fenders for 700cc tires will work with 27" tires.

Will they?

If not then where can I get some fenders for 27" tires?

Yes, they will work. I've done it. Several times :)

I can't believe any bike shop employee would tell you otherwise!!! 700C fenders can generally accomodate a wide range of tire widths, and consequently they must accomodate a range of diameters as well. The difference in diameter between a 700C rim and a 27" rim is only 8 mm. Fenders are made of a flexible material. I 100% guarantee that fenders meant for 700C tires will work with 27" tires!

The difference between a 700c rim and 27" is only 8mm in diameter. You will note than many tubes have both 700c and 27" tire sizes listed. It should work OK, though perhaps snuggly.

I've got Zefal CAB fenders on my 27's, (700c fenders of course) overall not a bad fit but the rear fender fans out quite a bit and looks kinda funny.

I also have the Zefal CAB fenders and had them on my 27" Takara. They fit just fine because they are fairly flexible. Recommended.

Yep, rode my 27 inch SS road bike conversion today. Freddy fenders hardcore work fine. They make 2 widths. Get the wider one if you want to use 27 x 1 1/4 or wider tires. If you're sticking to 27 x 1 1/8, then you could use the narrow fenders.

+1
I love my Planet Bike Freddy Fenders Hardcore... Flexible enough to deal with everyday banging around, strong enough to not worry. I run them on 27 x 1 1/4 and there's enough clearance. I'm pretty sure 700c fenders would do the trick as well. I bought mine at MEC for about $20 (CAD) plus taxes.

Wow. I was just thinking of this this morning. So a 700c will work, huh? What about width? I've got 1 1/4"-wide tires. Is that about a 28mm, do you think? Or wider?

I have very nice SKS P35 fenders on my road bike (700c wheels). Supposedly you're good with a tire up to 35mm; but I run a 28mm in front, and there's not a lot of clearance. If there's loose gravel or recently poured asphalt, I'll pick it up and get clogged every time.

1 1/4" is roughly 32 mm (1 inch = 25.4 mm)

Yes, you need to make sure that you get fenders meant for the appropriate width of tire. 700C/27" fenders typically come in 30 mm and 45 mm widths.

These are PB Freddies on 27" inch tires: