I have a Gitzo carbon fiber with the magnesium ballhead that the tripod (without the head) folds to 21.5 inches the combined weight is about 5lbs. It holds a Hasselblad with up to the 250mm lens as well as the 150mm + 2x with no problem. I haven't tried it with my 4x5 although it is rated to hold about 18lbs. I'm not sure how it will work with the bellows fully extended and I'm not crazy about using the 4x5 with a ballhead. The Gitzos are rather costly so there may be another brand with comparable capacities. I've had mine for a number of years and use it mainly when traveling/hiking. Around town or when convenient I use a larger and heavier tripod. There are shoulder straps that make carrying a tripod easier if you don't already have one. I think Domke still market them.

You can easily find the size, weight and capacity of most tripods online or better yet if there is a camera store with a decent supply of tripods take your equipment and try it out at the shop.

http://www.jeffreyglasser.com/