Empress Mills or Doughtys both do Wadding on the roll.
I bought some just last February at a Doughtys Roadshow, 15ms x 90" extra wide Ultra Clean Super Soft 100% cotton wadding (£10.99 per metre or just under £30.00 p 3 metres) for £115 and I dont think I will be buying any wadding anytime soon (or ever again)
The only concern that you have somewhere to store it!