I have been using Lomo Dry Bags for about a year now to store all my gear at wet rainy days at Knockhill, Cadwell, etc. Basically anywhere you have to store your gear outside. I also think they are a pretty good buy just to carry all your junk around to keep it all together and to save your car from getting dirty
They do various sizes but i have been using a 40litre one for my tyre compressor, nut gun and general tools and jackets and a 5litre one for camera gear and phones.
The prices are very reasonable compared to other outdoor shops. For example a 40litre bag is only £7.50
I originally used these bags for Kayaking and Climbing which is what they are designed for but are more than up to the job at track days.
If you place an on-line order could you please state that you are going to use them for track days in the "Enter any special delivery instructions:" section as i am going to enquire about having wheel bags made. This way they can see how much of a potential market there is

http://www.ewetsuits.com/acatalog/Dry-B ... gs-uk.html
Let me know what you think,
Mike