I think your layout is beautiful but I find that my eye finds the background fabric a little busy (at least for my taste). Would you consider using a more subtle (plainer) background fabric? Or perhaps using a narrower, plain colour (maybe a black or purple) to frame it & then using that background fabric as a wider border. Love the stained glass pieces though. Either way it is going to be a lovely quilt. My taste is more to simpler layouts & that is not to say yours is "way out there" because it is not, just a bit busy IMHO.

I love those blocks. You said the black lines are seams, and would not show in the final quilt. They do look like stained glass, but it will look very nice without the black lines, also.

I can see that there are only two different color layouts. Could you change some of the fabrics so that it's not so noticeable that the blocks in each column are the same. Some are upside down, but I would change blocks from one column to the other to make it look more like each block is unique.

And I agree with callen (and some others) that the background fabric is too busy. A more subtle, not so "printy" fabric would be better here. IMHO

Good luck on making your quilt. It will be beautiful.

I agree I think the bright yellow may be throwing you off, I like the yellow just not always in those same positions. Personally I like borders the same size and I notice the top and bottom borders are smaller than the sides. I like your design reminds me of Frank Lloyd Wright - Prairie Style.

I think the issue is you don't have enough change in value. It appears most of your colors fall into the same value range (medium). You have no lights no darks. I agree with the poster on the background fabric. In and of itself, it is beautiful but it does not make your panels sparkle like they could with a solid background. I would audition black, a dark charcoal gray, dark blue or go in the exteme opposite direction with a light. Such as cream, beige, light gray.

Here, I have attempted to insert your design in gray scale so you can better see what I am saying
[ATTACH=CONFIG]441725[/ATTACH]

Double yellows
 

I notice you have two yellows, one very luminous and the other more subdued. I think I would go with the luminous one only as it really sparks up the colors and if you did the whole piece would look more balanced. IMHO

I think it's perfect the way it is. Love it!

I would not change a thing. Its beautiful as is. Bind it with one of the dark colors in the border you show here. Please show us the finished quilt

Love the colours and it does look like stained glass. Have you tried putting corner stones in all the corners?

My initial thought was, I don't care for the background and border fabric. The print is too busy and detracts from the lovely piecing.

My feeling as I look at the quilt is that the quilt looks like it is in jail. I think the stained glass rectangles are too narrow for the sashing (or the sashing is too wide for the rectangles). I think it needs that narrow gold border to
offset the center of the quilt and I agree with the ideas of jazzykwilter. That's how I see and I waited to say this for a few days to let it percolate. Hope this helps as it is beautiful.