Wow, thank you PaulRivers. I also got a look at a Seek frame today. A seek1 I think. After measuring, I actually went home and pulled my studded wheel off my beater and went back to the LBS to check the clearance of the Seek frame. As far as I can tell, my Nokian 240 studded tires in 40mm will fit with fenders on the Seek. The LBS agreed. I also cursed the manufacturer for that stub that protrudes into the rear, stealing precious cm's of clearance. But I got the impressing that I would have at least 10mm of clearance between the studded tire and the fenders. Seek3 IS my next bike.

You weren't imagining things, 40mm studded tires ARE slow! But they do inspire a lot of confidence over the ice.