Followup on this posted to Latitude board:

http://forums.us.dell.com/supportforums/board/message?board.id=latit_general&message.id=46692

but in a nutshell, carefully applying a small amount of good themal compound to the head-transfer assembly (where it mates with the cpu chip die) makes a HUGE difference. The fan cycles on rarely now and only on low speed. I ran Dell Diagnostics and both fans are working properly (that was probably a static problem or perhaps plug pin needed reseating).