Well done - these look great - and yes I do believe they would sell.
I am assuming by the photos that the strap is sewn on the back. I did something similar with a one strap and sewed one part on the front of the bag and the other on the back so it looks crossed (did that make any sense at all?)
I like the look of the rings. The strap looks like webbing - is it adjustable? And the bag looks big in length - what are the dimensions out of curiosity?
I like the black one with what looks like purple patchwork going across it.
Great job - well done you