There's a really interesting compact USB keyboard referenced in a couple of old threads.
I just got one of these keyboards for my N810. $25 delivered.
http://cgi.ebay.com/Portable-Super-S...QQcmdZViewItem
It's an ideal size, and decently made.
Worked for Thoughtfix on his N800, half works for me on my N810.
Caps Lock, Num Lock and Scroll luck all lit and active, can't turn 'em off.
There must be some way to beat this, but I don't know what I'm doing.

dmesg output follows.

[ 1862.554687] EAC mode: play enabled, rec enabled
[ 1868.851562] EAC mode: play disabled, rec disabled
[ 1892.148437] tusb_source_power 629: VBUS a_wait_vrise, devctl 19 otg 174 conf c0010000 prcm 00a80500
[ 1921.328125] musb_stage0_irq 570: VBUS_ERROR in a_wait_bcon (91, <VBusValid), retry #1, port1 00000100
[ 1921.585937] musb_stage0_irq 646: CONNECT (a_host) devctl 3d
[ 1921.585937] hub 1-0:1.0: state 8 ports 1 chg 0000 evt 0000
[ 1921.585937] usb usb1: usb auto-resume
[ 1921.585937] usb usb1: finish resume
[ 1921.593750] hub 1-0:1.0: hub_resume
[ 1921.617187] hub 1-0:1.0: port 1, status 0301, change 0001, 1.5 Mb/s
[ 1921.773437] hub 1-0:1.0: debounce: port 1: total 100ms stable 100ms status 0x301
[ 1921.898437] usb 1-1: new low speed USB device using musb_hdrc and address 2
[ 1922.046875] usb 1-1: skipped 1 descriptor after interface
[ 1922.046875] usb 1-1: skipped 1 descriptor after interface
[ 1922.046875] usb 1-1: default language 0x0409
[ 1922.046875] usb 1-1: new device strings: Mfr=0, Product=2, SerialNumber=0
[ 1922.046875] usb 1-1: Product: USB K/B
[ 1922.046875] usb 1-1: device v05af p0807 is not supported
[ 1922.046875] usb 1-1: uevent
[ 1922.046875] usb 1-1: usb_probe_device
[ 1922.046875] usb 1-1: configuration #1 chosen from 1 choice
[ 1922.054687] usb 1-1: adding 1-1:1.0 (config #1, interface 0)
[ 1922.054687] usb 1-1:1.0: uevent
[ 1922.054687] usbhid 1-1:1.0: usb_probe_interface
[ 1922.054687] usbhid 1-1:1.0: usb_probe_interface - got id
[ 1922.054687] drivers/usb/input/hid-core.c: HID probe called for ifnum 0
[ 1922.070312] input: USB K/B as /class/input/input4
[ 1922.070312] input: USB HID v1.10 Keyboard [USB K/B] on usb-musb_hdrc-1
[ 1922.078125] usb 1-1: adding 1-1:1.1 (config #1, interface 1)
[ 1922.078125] usb 1-1:1.1: uevent
[ 1922.078125] usbhid 1-1:1.1: usb_probe_interface
[ 1922.078125] usbhid 1-1:1.1: usb_probe_interface - got id
[ 1922.078125] drivers/usb/input/hid-core.c: HID probe called for ifnum 1
[ 1922.093750] drivers/usb/input/hid-core.c: submitting ctrl urb: Get_Report wValue=0x0101 wIndex=0x0001 wLength=2
[ 1922.101562] drivers/usb/input/hid-core.c: submitting ctrl urb: Get_Report wValue=0x0102 wIndex=0x0001 wLength=4
[ 1922.101562] input: USB K/B as /class/input/input5
[ 1922.101562] input: USB HID v1.10 Device [USB K/B] on usb-musb_hdrc-1
[ 1922.101562] drivers/usb/core/inode.c: creating file '002'
[ 1922.101562] hub 1-0:1.0: 100mA power budget left
[ 1922.101562] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[ 1922.101562] hub 1-0:1.0: port 1 enable change, status 00000303
[ 1937.304687] EAC mode: play enabled, rec enabled
/home/user #

Any of that mean anything to anyone?