Cyclocross - Cyclocross tires and caliper brakes/road fork

Hey all, I'm putting together a fixed gear/single-speed bicycle based on a Raleigh Technium road bike frame. I've been wanting to build one for a while now, and while I intend to ride it all year I was looking forward to taking advantage of fixed gear traction and maintainability for snow riding. To that end, I was hoping to slap on some cyclocross tires with a good tread on them, but I'm quickly coming to the realization that that's kind of a naive idea given the clearances of a standard caliper brake and road fork. Has anyone tried this? Are there any combinations of tire size/caliper that will work okay, or should I give up on this idea entirely and just wait until a cyclocross frame with actual cantilever bosses comes my way to build the tough winter bike I had in mind?

That's a tough one. The best you can probably do is a 23c or 25c road tire with some all season tread. They won't be too knobby for deep snow but may give you enough tread to get you through the easy stuff. Here are a few I found in that range:
Panaracer Pasela, 700x25c
http://cdn.mos.bikeradar.com/images/bikes-and-gear/components/tyres/road/CYP217.tyres.panpas-399-75.jpg
Schwalbe Marathon Plus, 700x25
http://static2.bicycletires.com/images400/scmar-1.jpg

If you can take a 28 there is this one from specialized:
Infinity Armadillo, 700x28
http://www.specialized.com/media/equip/0004-5001_0006-5085_d.jpg

A lot of it depends on how much clearance your frame has. Best case, you can do this:

http://farm3.static.flickr.com/2688/4044721376_590338a22a_m.jpg

But realistically, you probably don't have that much space.

The Michelin Mud2 is the skinniest CX tire I know of. It doesn't have any edge knobs, but that helps you as long as you aren't making any high speed turns.

You can get a new version of the Dia Compe brakes pictured above. Tektro makes more contemporary looking caliper brakes (http://www.universalcycles.com/shopping/product_details.php?id=15985&category=3154) with a lot of clearance, but the minimum reach may very well be too much for your frame.

Two tires that might help your challenge are the Schwalbe CX Comp and the Schwalbe CX Pro. These come in 700c x30, and are still real cyclocross tires with real deep knobs (purists will argue that clinchers can never be real cx tires, ah!).

Personally, I'd change the road fork for one with more cleareance and canti/V-brake bosses, or better yet disc tabs. This will let you use a wider tire up front which is useful for wet weather riding as it helps avoid taking spills during the turns. I just did this on one of my frames. Running 32mm front/28mm rear works like a charm.

I have this tire mounted on a Reynolds Ouzo Pro road fork / Dura Ace caliper brake. No problems with clearance. I like the tire alot (other than the price). I ride fire roads / double track and even the occasional single track with it.

http://www.biketiresdirect.com/pcoclj/continental_top_contact/pp.htm

Wow, thanks for all the suggestions. I'm picking up the frame on friday so I'll get to figure out then whether I want to go with one of the tires linked upthread or maybe switch out the fork. Cheers!