Been busy packing of late (what with moving next weekend and all), so I haven't had the chance to make a huge amount of progress. I _do_ finally have solid colour backplanes working correctly though, which is nice (screenshots to follow at some point in the future). The code deserves some kind of award for being the most complex component in the system in proportion to the hardware function it's implementing. Still wondering if maybe I should have gone with the software renderer option after all... In any case, the clock etc bios screens do look nicer with the proper background gradients on them.
I've also discovered that the PVR really doesn't like trying to do alpha blending in the opaque polygon list. Of course, some would say that that's the _point_ of having separate opaque and translucent lists, but it would have been nice if it failed in a clean, easily implementable way, rather than by going through some relatively complex display screwups... Bug compatibility, natch. Also, dest blending modes 4-7 don't seem to match up too well with Maiwe's list, unless they're intended to mean something other than what GL expects them to mean.
 By the looks of it it's not clearing out the tile before drawing over the top of it, which isn't terribly surprising, except that it's from 2-3 tiles back rather than the last tile.
 I haven't gone through all the src blend modes yet, but I'm guessing that similar caveats may apply.