After a week or ten days of work, I had things working fairly well. Power management was acceptable (although Fn+F4 didn't seem to reduce power consumption very much - I am accustomed to leaving my machine in this state overnight without trouble, but the R31 would only last a matter of a few hours before the battery became exhausted). I had VMware installed and working properly (although full-screen mode was not properly supported).

Then the machine started locking solid on random occasions. The only way to recover was to power off. I thought perhaps it was temperature related (in at least one instance I'd had the machine on my lap for some time), but it has happened even with the machine (relatively) cold. I suspected my new RAM, but it happens with either 512M SODIMM installed (and the other absent) - unless both SODIMMs have failed (extremely unlikely, in my opinion) that's not the problem. It was suggested that I had misconfigured the kernel, so I went back to the stock 7.3 install and rebuilt with as few changes as I could manage (enable APM, disable agpgart in preparation for using Xi's graphics drivers). I also thought perhaps I was telling the kernel it had more memory to work with than was really the case (I gave it 1000M, whereas the correct value might have been 976M since there are two pipes, and my earlier investigations with XP's device manager suggested BIOS had allocated 24M to each); I tried 960M and it made no difference.

I don't know if the problem is flaky hardware, flaky APM BIOS, user error, or some combination thereof, and I can't spend any more time trying to diagnose it further. I'll try a more Linux-friendly machine (A or T series) in a few weeks...

Good luck to those of you who stick with your R31s; I hope the little information presented here proves of use to you.