Aire PVC kayak material...
AIRE PVC Kayak Material at NRSweb.com
I own some of this fabric and it's relatively light and supple compared to most PVC rafts, but still seems plenty durable. The nice thing about this material is that it's sold by the foot, so you could order longer continuous sections. I've used it only for shoring up wear spots, but that seems appropriate from what you want to do.
Also, from what I've heard, urathane can be glued to PVC with Clifton Urathane Adhesive. The only issue is that NRS seems to be selling their urathane material in smaller chunks rather than off rolls... maybe they can sell you a longer piece if you try?