Art supplies stores in HK

Which art supplies stores sell the large size canvases?

I am looking for a square large size canvas that is in the range of 48" x 48" and 60" x 60", and a circular canvas that 30" x 30".

I also want to know the prices, especially if they can make the sizes which they don't sell in the stores.

Epsecially for the larger one, I don't want to spend over $1000 to buy a single canvas. If I am better to mount the canvas by myself, please let me know where I can buy those stretcher strips and canvases, and how much they are.

Preferrably the stores in HK Island, and Kowloon. The closer to Eastern area the more preferable. Thanks.