As far as using a G5 to host thin clients, there are two potential solutions:
1: renounce all desire to ever touch or use or think about any software you couldn't run on linux, and then set up X11 and use a normal X11 display terminal, like you might on an SGI or Sun system. An alternate version of this option is just to turn off the Mac and actually use an SGI or Sun or linux/bsd system with one of those types of devices. (HP Envizex is an X11 client that I can remember off the top of my head, there are others.) (Although I imagine this isn't what you'd had in mind... [
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2: VNC, which isn't really that great, requires huge network bandwidth and still is kind of terrible, but a VNC server is built into OS X. A device like the decTOP or most of the thin clients from WYSE and HP should hypothetically be able to do VNC. At absolute worst, an atom-based nettop running Windows XP would do the job. However, unlike RDP and X11, there's a huuuuge quality and experience loss when you're using VNC.
There's this company that built an RDP server for OS X, with the intent that you could hook the SunRay Windows Connector into a farm of xserves running their RDP product, and have a realistic mac thin client set up. However, my understanding is that their product is somewhat terrible, and that it's extremely expensive to license, more than it'd cost to get proper terminal services licensing for Windows, based on what the web site looks like.
Also, the university here has 10.5 on a few G5s (well, we've got one left, the others were replaced by mac minis) and it looks good. I don't know how much ram ours have, but my recommendation is always to put as much memory as a computer can reasonably handle in it. If I had a G5, I'd probably be working on maxing it out before DDR1 (or DDR2 for newer G5s) got too much more expensive than DDR3 currently is.
1: renounce all desire to ever touch or use or think about any software you couldn't run on linux, and then set up X11 and use a normal X11 display terminal, like you might on an SGI or Sun system. An alternate version of this option is just to turn off the Mac and actually use an SGI or Sun or linux/bsd system with one of those types of devices. (HP Envizex is an X11 client that I can remember off the top of my head, there are others.) (Although I imagine this isn't what you'd had in mind... [
] ]'>2: VNC, which isn't really that great, requires huge network bandwidth and still is kind of terrible, but a VNC server is built into OS X. A device like the decTOP or most of the thin clients from WYSE and HP should hypothetically be able to do VNC. At absolute worst, an atom-based nettop running Windows XP would do the job. However, unlike RDP and X11, there's a huuuuge quality and experience loss when you're using VNC.
There's this company that built an RDP server for OS X, with the intent that you could hook the SunRay Windows Connector into a farm of xserves running their RDP product, and have a realistic mac thin client set up. However, my understanding is that their product is somewhat terrible, and that it's extremely expensive to license, more than it'd cost to get proper terminal services licensing for Windows, based on what the web site looks like.
Also, the university here has 10.5 on a few G5s (well, we've got one left, the others were replaced by mac minis) and it looks good. I don't know how much ram ours have, but my recommendation is always to put as much memory as a computer can reasonably handle in it. If I had a G5, I'd probably be working on maxing it out before DDR1 (or DDR2 for newer G5s) got too much more expensive than DDR3 currently is.