Just copying the links mentioned in the above thread hopefully to make our research easier :)
(Most of these links are for Japanese website, you can use http://world.altavista.com to make a barely-readable translation of them).
http://www.panasonic.co.jp/pc/prod/note/01xsaapj.html (Panasonic ProNote homepage)
http://www-6.ibm.com/jp/pc/thinkpad/tppen84/tppen84a.html (IBM 2435 -003 homepage)
http://www5.big.or.jp/~yosizawa/pc/2435/ (Pictures of IBM 2435 (CF-01) internals)
http://homepage1.nifty.com/ohta/2435/batt.htm (Battery hack)
http://www2s.biglobe.ne.jp/~t-toku/gi2435.htm (IBM 2435 hack\fansite)
http://www.panasonic.com/computer/notebook/html/04b.htm (Pen Services download)
http://pencomputing.com/frames/pana_cf01.html (Preview from Pen Computing Magazine)
Thanks to Pete, JunkLeo, mfkap, Groch for posting the links.
-paqman