Looking at doing the Welsh Ride Thing which involves 2 nights out and can see that there is a potential for fitting a reasonable size bag under the crossbar, problem is that this is on a Blur so would have to be below the shock. Has anyone got a source of such a bag or any tips for bodging? The ones used for that trip Chipps did in the Pyrenees looked good but as I'm not looking for this camping thing to be a habit, can't justify £100+ for a bag. Any thoughts?