Has anybody tried using those internal PCIe storage cards in a Late 2005 Power Mac G5? Shouldn't they work in theory? Things like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16820227709
there were some "oem" silicon 3132 that could be used with the G5 (I don't know if it needs flashing) Like this one http://allegro.pl/unitek-pci-express-2x-sata-ii-wewn-raid-gw-new-i3315349294.html info from user hwojtek , given to me a couple months ago.
If you want theory, here it is: First revision of Revo was using Sil3124 controller. There's a 10.4 and 10.5 PPC driver for this chip, so theoretically it could work. However, there's also PI7C9X130 bridge chip converting PCI/PCI-X signal to PCIe. If it's transparent for OS, Revo will work. If it isn't - it won't.
Big question is, is it bootable on a PowerMac G5? I am guessing it is not. If it will work on Leopard it means that it is only good for storage?
It doesn't have to be bootable, but it would be faster than SATA 1 and a good way to store in general.
Revos are cheap nowadays, esp. first gen., so maybe it's worth to try. I think that this bridge chip is transparent for OS. Ensure that you're buying Sil3124 based one. Drivers are available on Silicon Image website.
AMCC 3ware 9650SE line is 100% compatible (also sold under the brand LSI). Driver's are found on their website. It is not bootable, though. Fun fact: it uses a PowerPC chip on the card.