You can use any stylus intended for tablet PCs utilizing Wacom technology. This includes all ThinkPad X series convertible tablets, many Fujitsu Stylistic and Lifebook tablets, many Motion Computing tablets, many HP convertible tablet PCs, the Axiotron Modbook, etc. Obviously only Lenovo pens fit in the pen slot.
X60 tablet 6363-P3U, 3GB ram, 128GB SanDisk Extreme SSD, SXGA+ screen, Intel 6300
T61 Frankenpad in 15 inch T60 body, UXGA LED-lit AFFS LCD, T9300, 6GB RAM, Intel Graphics, Intel 6205, 128GB Crucial M4 SSD, 1TB HGST HDD + eBay caddy in Ultrabay
701c butterfly, 75MHz 486DX4, 40MB ram, 1GB CF card