Gunnie -
I don't know what OS the "watch" runs, but there is a rugged PDA that runs Windows Mobile 2003 for Pocket PC, and Exbal runs under that.
It's expensive (around $1200), but it's for field technicians and others who work outdoors, so it can get rained on and dropped onto concrete. While it doesn't look like a "tactical" product, I imagine it would work quite well for civilian applications where muted colors aren't a requirement.
Here's the link -
http://www.ruggedpcreview.com/3_handhelds_tds_recon.html
(I haven't gotten this serious yet. The closest I have is a "splashproof" laptop made by Panasonic. Based on my many needs for a computer, I need full capability rather than hand-held. However, technicians often need something that fits in one hand.)
OK, I looked up 5.11 watches and I got -
http://www.511tactical.com/index.asp?pageID=watchinfo
This says the watch runs Horus Vision ballistics software. I don't see any provisions in this watch for downloading different software. It isn't a PDA, just a watch with a ballistics calculator.
IMO, if you really want all the bells and whistles of Exbal, you have to have either a PC (laptop or desktop), or a supported PDA (Palm OS or Windows Mobile OS.)