Berkey Travel, with the extra cartridges to remove fluoride. It is stainless steel.

I got mine from Pleasant Hill, and am very happy with it:

http://www.pleasanthillgrain.com/berkey_light_big_berkey_water_filter_british_berkefeld_portable_purifier.aspx

Travel Berkey® with Black Berkey® Water Purification Elements

Travel Berkey® Capacity & Flow Rate: The Travel Berkey is the second-smallest Berkey® system. Its very compact nested size makes it a great travel companion. It comes equipped with two Black Berkey® purifying elements, which the maximum it can accommodate. Lower storage tank capacity is 1.5 gallons. Flow rate is 2.75 gallons per hour with two elements. The Travel Berkey® system can purify up to 66 gallons per day when the upper chamber is full.

The Travel Berkey® system nests to a size of just 7.5" x 12", compact enough to fit in a suitcase. The Travel Berkey is the perfect combination of capacity and mobility for easy, reliable water purification.

Dimensions: 7.5"D x 18"H (12"H when nested for storage or transport)

There are some cute little portable and mobile reverse osmosis filter systems, though they do have to be hooked up to a running faucet to work.

Reverse osmosis can remove up to 90% of fluoride, not nearly as much as the activated alumina Berkeley filter that PaleoGran suggested.

You should check with the manufacturer to make sure that it actually removes fluoride. They commonly do, but it varies depending on membrane type and the size of the pores.

Google "portable reverse osmosis filter" or "mobile reverse osmosis filter", and you'll get a bunch of hits. Amazon even sells a couple, apparently.

This one specifically states that it removes fluoride -

Portable Reverse Osmosis Water System

All I know of is a reverse osmosis system, but that's not portable. However, you could do that and occasionally get bottled water from the store that is reverse osmosis for portable use.

Someone sent me this link. http://purewaterfreedom.com/osc/remove_fluoride.php anyone use this brand? I am seriously thinking about getting one.

The FluorideMaster whole house filter system filters fluoride out of typical municipal water. Its a more reasonable option than the whole house reverse osmosis systems. Its not perfect, but at less than $1,100 it is reasonable. It uses a large amount of bone char, which does an excellent job with typical municipal water, and it has a 6 month money back guarantee. The after-the-sale support has been very good for us. Maintainance is straightforward and not a burden, time-wise or money-wise.

Installing a good quality whole house filter for chlorine was our priority upon learning of the dangers of the contaminants in our municipal water, especially chlorine and chlorine by-products, which caused asthma-like reactions in the shower. They also contribute to thyroid problems and cardivascular disease. How? Chlorine replaces iodine in the thyroid gland, which then malfunctions, which leads to hypothyroidism and weight gain. Chlorine in the bloodstream damages blood vessels continuously and the body is constantly repairing all of the damage without a break: slowly, calcification of the arteries occurs. For chlorine filtration our family decided on the PureMaster V-700 whole house system. It also filters out heavy metals, and other contaminants, including - chloramines, cysts, copepods, VOCs, atrazine, benzene, xylene, pesticides, insecticides, herbicides. It had a great price for its large capacity and after-the-sale support has been very good.

The PureMaster/FluorideMaster combo is a good deal.