Here's a link to the Holt's site with the Savoy humidors. I think the red and blue are on sale for 40% off.
They're nice humidors, and not a boatload of money.
Most travel humidors don't hold many cigars, plus I agree you shouldn't expose your entire collection to the extremes of temperature in a car. Some websites will give you a free travel humidor with certain orders (check out Famous).