I must agree, adding a SCSI card to an Apple IIgs is a brilliant move...as is some extra RAM.
Ended up purchasing two cards from GGLabs...an original Apple SCSI card...WAYYYYY too expensive now. One went into the IIgs with an Applied Ingenuity Inner Drive 20 [integrated power supply and hard drive, which is not SCSI] and one of these cards. Best of both worlds there...and the other, pictured, just a vanilla IIgs with the SCSI card and an external BlueSCSI v2 neatly tucked inside....the sleeper IIgs. =D. Of course, this setup does kill using external SCSI devices, but that's OK -- three drives [two 32MB ProDOS, one for the active GS/OS startup, one for a backup of the spinning platter drive in the other IIgs and one 500MB HFS drive for storage].
This little setup has worked out quite nicely. What was the uphill climb, finding a good set of GS/OS disk images to get things fully installed and patching disks with the needed GGLabs driver. Once that was done, let the fun begin!