The article of mine that Gavin Wraith refers to above can actually be found online. I put a copy on some personal Web space to show to someone ages ago, and forgot to remove it afterwards, so it isn't part of the official FRU Online site or linked from anywhere else. Anyway, I might as well leave it there for the time being in case anyone wants to read it. It's pretty long, but it does go into a large amount of detail about how I created the RISC OS 5 icon set, and some of the associated challenges, goals and underlying ideas. Here's the link:
lym: "I'm guessing, however, that it's still stuck with granite grey for the windows"
Well, the Iyonix window-background texture is actually 'paper', and it's strictly not grey. (As the above-linked article explains, the paper texture actually uses lots of pale colour-noise to give an impression of 'warmth', rather than the starkness of pure grey-scale pixels.) But the overall effect is of a pale grey of the usual Wimp Grey 1 intensity, yes. (I do think that my texture works a lot better than the RO4 marble effect though.)
"and that irregular-shaped icons can't benefit from the background blending and alpha channel allows."
The RISC OS 5 icons were designed from the outset with alpha blending in mind, and the fact that they don't use that feature at present is simply due to the fact that RISC OS 5 currently doesn't support it. If that support were forthcoming at some future point, it should be relatively easy to regenerate the RO5 icons in alpha-blended versions, which feature 'real' shadows etc., and this is something that I'd very much like to do. It's a feature that I've wanted on the Iyonix ever since its release.
The thing to bear in mind is that RISC OS 5's feature set is very similar to that of RISC OS 4.0x, and so there are things that it can't do that Select /can/ do. It's always struck me as rather ironic that RO5, which doesn't support alpha-blended icons, has an icon set that would benefit hugely from that feature, and could really make good use of it, whereas RO Select *does* support alpha-channel sprites but doesn't have a suitable set of sprites to take advantage of the feature. The only novel icon-related feature of RO5, compared with RO4, is the support for high-definition icons (in EX=0, EY=0 screen modes). RO4 actually supports this feature but has no icons to take advantage of it; my RO5 set includes a full complement of high-definition icons. RO5 also supports high-definition window tools (and, again, includes a set), whereas RO4 doesn't support them at all.
What I'd personally love to see in future is a universal adoption of my RO5 sprites for future versions of RISC OS, suitably updated to take advantage of alpha-blending. I'd be more than happy to do the necessary work to generate the new set. Perhaps this is something that could happen via RISC OS Open (but that's just speculation; no-one has approached me about it yet, and it would have to be done with Castle's agreement).
I'm personally not a fan of rounded and/or graduated-filled button icons. I'm not against them in principle, but I've yet to see any under RISC OS that look anything other than appalling. What I'd like to see is some way for more sophisticated button icons to be drawn out of alpha-blended graphical components. The current shading options in Select just don't cut it, and the rounded-edged buttons, which lack even basic anti-aliasing, look dreadfully amateurish.