Try searching some of the bushcraft forums for more info - a lot of folks use them for dehydrating meals for wilderness trips.
I made a simple one myself. It's basically an insulated wooden box, lined inside with tinfoil, and heated with an everyday incandescent light bulb. I also installed a 12V computer fan (optional, but I think it helps) that sucks a wee bit of fresh air in, and recirculates the rest to promote drying. The food is placed on wire cooling racks (the same as you use to cool cakes), or for liquids, in wooden trays covered with greaseproof paper. The key thing is to get the temperature right so that the food dries quickly but doesn't cook.
I've used mine successfully for drying fruit such as apple rings, and for making 'fruit leathers'. Dried slices of kiwi fruit are great - they taste just like candy. Veggies such as mushrooms dehydrate down to nothing, and can then be added into stews etc later, whereupon they rehydrate and become like, well, mushrooms!!
So, sorry I can't recommend a brand or anything, but don't be put off trying with whatever DIY solution you have, whether that be an airing cupboard or even the parcel shelf of your car on a hot day! Also, talking of solar dehydrators,
here's a link, or
even two that may be of use.
HTH!