Folding Bikes - Big rack bag?

I'm sure I once saw pictures of somone with a rack bag big enough to fit their stuff in for a tour (no side pannier bags).
I've been scouring the internet, but all the rack bags seem too small. Anyone know if a capacious rack bag is available (preferably in the UK)

Many thanks.

Carradice has a nice rack bag that is expandable.

http://www.carradice.co.uk/rack-packs/index.html


I dont use a rear rack on my folder because it is just one more thing to remove and re install every time I pack, So I use another carradice bag that is the size of a rack bag and I adapted a klickfix QR system.

http://s164.photobucket.com/albums/u11/bicycleflyer/My%20Projects/?action=view&current=Picture118.jpg

http://s164.photobucket.com/albums/u11/bicycleflyer/?action=view&current=Picture123.jpg

My wife just bought this 46 liter duffle for the back of her Moulton TSR:
http://www.chinookmed.com/cgi-bin/category.cgi?item=03732BL&type=store

She originally wanted the rack bag specially made for the TSR by Carradice, but it doesn't appear to be available anywhere. Anyway, this duffle is waterproof and really good value. It seems to be very well made.

Downsides? We haven't actually toured with it yet, so we will find out how well it works in practice and how durable it will be. It doesn't have bike-specific straps, so will be bungeed to the rack. The TSR rear rack is longer and wider than most - so although it seems to fit well, it may not work on other bikes. Check the measurements of your rack...

I like the xootr crossrack (http://www.xootr.com/crossrack-bike-rack.html) plus an arkel utility pannier (although you can use any pannier). I haven't used this for touring (I use conventional front and rear panniers), but it works well for grocery shopping around town.

The achilles heel of all of the one-bag systems is the weight limit; I haven't found one that holds more than 25 lbs.

The Axiom Odyssée (http://www.axiomgear.com/product/racks/seatpost_racks/product.php?id=149) takes 25 kg!