Sorry, I've been dealing with this for months, let me try to gather up more info: 2.6.34 worked perfectly.  The Nov 9 log was using kernel 3.0.6 I believe.  3.1.0 had the same problem.  Right now, I'm using this:

Linux dune 3.1.6-gentoo #1 SMP Mon Jan 2 13:51:06 EST 2012 x86_64 AMD Phenom(tm) 9850 Quad-Core Processor AuthenticAMD GNU/Linux

The problem seems to have dissipated some with this kernel.  I can mount the raid and ls the contents.  But after a while it became unavailable.  I'll try to gather more information.  Let me know if there's something specific I can provide.  Here is dmesg output, the Sans Digital MobileSTOR MS2UT+B raid1 is ata4:

ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata3: softreset failed (device not ready)
ata3: applying PMP SRST workaround and retrying
ata1: softreset failed (device not ready)
ata1: applying PMP SRST workaround and retrying
ata4.15: Port Multiplier 1.1, 0x1095:0x5744 r33, 2 ports, feat 0x1/0x9
ata4.00: hard resetting link
ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata3.00: ATA-8: ST31500341AS, SD1A, max UDMA/133
ata3.00: 2930277168 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata3.00: configured for UDMA/133
usb 4-1: new low speed USB device number 2 using ohci_hcd
ata1.00: ATA-7: ST3400620AS, 3.AAC, max UDMA/133
ata1.00: 781422768 sectors, multi 16: LBA48 NCQ (depth 31/32)
ata1.00: configured for UDMA/133
scsi 0:0:0:0: Direct-Access     ATA      ST3400620AS      3.AA PQ: 0 ANSI: 5
sd 0:0:0:0: [sda] 781422768 512-byte logical blocks: (400 GB/372 GiB)
sd 0:0:0:0: Attached scsi generic sg0 type 0
scsi 2:0:0:0: Direct-Access     ATA      ST31500341AS     SD1A PQ: 0 ANSI: 5
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 2:0:0:0: [sdb] 2930277168 512-byte logical blocks: (1.50 TB/1.36 TiB)
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 2:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sdb: sdb1
sd 2:0:0:0: [sdb] Attached SCSI disk
 sda: sda1 sda2 < sda5 sda6 > sda3 sda4
sd 0:0:0:0: [sda] Attached SCSI disk
input: Logitech USB Receiver as /devices/pci0000:00/0000:00:12.1/usb4/4-1/4-1:1.0/input/input2
logitech 0003:046D:C517.0001: input: USB HID v1.10 Keyboard [Logitech USB Receiver] on usb-0000:00:12.1-1/input0
logitech 0003:046D:C517.0002: fixing up Logitech keyboard report descriptor
input: Logitech USB Receiver as /devices/pci0000:00/0000:00:12.1/usb4/4-1/4-1:1.1/input/input3
logitech 0003:046D:C517.0002: input: USB HID v1.10 Mouse [Logitech USB Receiver] on usb-0000:00:12.1-1/input1
ata4.00: SATA link up 3.0 Gbps (SStatus 123 SControl 320)
ata4.01: hard resetting link
usb 4-2: new low speed USB device number 3 using ohci_hcd
ata4.01: SATA link down (SStatus 0 SControl 320)
ata4.00: ATA-7: External Disk 0, 1.1583, max UDMA/133
ata4.00: 2930277168 sectors, multi 1: LBA48 NCQ (depth 31/32)
ata4.00: configured for UDMA/133
ata4: EH complete
scsi 3:0:0:0: Direct-Access     ATA      External Disk 0  1.15 PQ: 0 ANSI: 5
sd 3:0:0:0: [sdc] 2930277168 512-byte logical blocks: (1.50 TB/1.36 TiB)
sd 3:0:0:0: Attached scsi generic sg2 type 0
sd 3:0:0:0: [sdc] Write Protect is off
sd 3:0:0:0: [sdc] Mode Sense: 00 3a 00 00
sd 3:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sdc: sdc1
sd 3:0:0:0: [sdc] Attached SCSI disk
kjournald starting.  Commit interval 5 seconds
EXT3-fs (sda4): mounted filesystem with writeback data mode
VFS: Mounted root (ext3 filesystem) readonly on device 8:4.
Freeing unused kernel memory: 592k freed