I thought since I'd finally managed to track this down, I thought I'd start a thread to record the information for everyone's benefit.
From what I've learned searching the net, the RF98-2 (the FC version from that year with the bolt-on roll bar) used double-row wheel bearings with dimensions of:
OD: 88mm
ID: 49mm
W: 46mm
A little digging turned up a part number of SNR GB40279 S01, and the SKF Parts Interchange website lists that part as being the same as their GRW506, and that it was used as the rear wheel bearing on Mercedes-Benz models:
400E 93-92 (Hey: that's how SKF wrote it!)
400SE 1992
400SEL 1993...
...and numerous other numbers from 420 to 600 (with various suffixes), all in the 1991 to 1993 model years.
As I understand it, these bearings were probably used from 1998 on to the present models still made by Elan
I came looking here, and found the basic dimensions and one part number, so I thought I'd leave things a little better for the next racer who came looking.