[Becco_UK]

I know bugger all about about architecture but this looks good to me. Perhaps composit a real sky in and use a similar hdr image for refections and refraction would add to the realism. The 'red' looks slightly orangy on my monitor ( is Maxwells' 'physical' sky messing with your colours?).

[Bubbaloo]

Thanks for the comments! I actually finished this a while back and posted it in my gallery. Although I need to re-post it because it was originally hosted on metoric.de, which is no more...

The final version, although it has more details added, isn't as "finished" as I would like. It's still lacking a proper sky and env reflections in the glass.