Do you absolutely have to add exterior siding to ICF homes? I love the look of exposed concrete and want to avoid the cost of siding and drywall altoghether. Can that be done? This is for application in Ontario, Canada where cold weather is a factor. Are there specific brands of forms that would be more suitable to such an application? There is probably a bunch of products that could simulate the look. But I want to know if it's possible to add a sealant or something directly to the exterior and interior sides to create the look of the photo below.

Most jurisdictions will require you to cover the exposed foam inside the house for fire protection. I don't know if EIFS stucco inside would be acceptable fire protection. Maybe it would. Would it get you the look you want?
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You want a CIC wall. Concrete, insulation, Concrete

I like that minimalist modern style too.

We make a tilt-up icf wall system that would allow you to have eps insualtion on one side and exposed concrete on the other. Leaving the concrete exposed on the outside from an energy stsndpoint is not the best way to get energy performance. However, it can be done if you don't mind giving up the energy savings. Concrete sealants are available to seal the concrete, but will have to be done on a regular scheduled maintance period to keep the surface sealed. These sealer wear off over time. There are elastromeric paint coating for concrete & masonary surfaces that are pleasing to the eye and that do offer waterproofing. At the end of the day your efforts to construct such a structure are going to be time consuming, not very energy effiecent, and possiblly more costly than going the normal icf wall system with a cement stucco plaster to simulate a concrete veneer. The final icf just described would give you the most energy efficent, and cost effective structure for your money, as well as a lot less headaches. If we can be of any other help contact us at www.versa-form.com (go the the contact us page).

Dale

It became pretty definite that ICFs were not an option for this kind of finish. I had hoped that Durisol or some similar form that seem to include cement board in the form material could be used to simulate the look. But no, not quite.
Anyway, thanks for your responses.

if you like the look of exposed concrete or masonry you could use

http://www.quadlock.com/retrofit_insulation/
www.insofast.com

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check out the saebi alternative building system (SABS) or metrock SCIP. They are concrete layers sprayed on the outside of eps foam panels.

I believe the Saebi Alternative Building System has the potential to be the least costly system provided it is promoted enough to make it readily available.  Of course, the ultimate price will heavily depend upon the marketing position taken by the company.