I have one of these. I got it for motorbiking and it's a bit bigger than I'd use on the road bike (but I'm pretty obsessive about having the smallest saddle bag I can get away with), but it's great, no bigger than some of the ones posted above, has millions of elastic loops, a sealable compartment, rolls flat, would take a glued tub, is indesctructible and would last forever and is half the cost of the Rapha.
I haven't experimented, but it may mount to saddle rails using the standard closing strap, or could be modified with a toe clip or bit of velcro strip.
http://www.kriega.com/products/Tool-Roll.html
I have one of these. I got it for motorbiking and it's a bit bigger than I'd use on the road bike (but I'm pretty obsessive about having the smallest saddle bag I can get away with), but it's great, no bigger than some of the ones posted above, has millions of elastic loops, a sealable compartment, rolls flat, would take a glued tub, is indesctructible and would last forever and is half the cost of the Rapha.
I haven't experimented, but it may mount to saddle rails using the standard closing strap, or could be modified with a toe clip or bit of velcro strip.