Cooling a house without forced air.

I'm working on an expensive custom home that will be built in a high-end neighborhood located in a northwestern state -- meaning there really are only 2-3 warm months (at most) per year. The client intends to use a hydronic radiant in-floor heating system to warm the house during cold weather. But, now he's wanting to add a forced air system to support air conditioning in warmer weather. Our client expects to live in this house with his family -- he's reasonably confortable with the passive cooling solutions we've proposed, thinking he and his family would be fine during the warmer months. But, he's increasingly concerned that not having a forced air system will negatively affect his resale value should he decide to sell this house down the road. Anybody else encounted this issue before? Any good alternatives to a forced-air cooling system?

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