i've been trying to find a better handline as well -- something to carry with me on my surfing kayak, when I can't carry anything big. here are some of thing things i've found (only one of which is really suitable for me):
this is the streamlines handline, the smallest available, professionally made, comes with instructions; but maybe it's only good for ponds and streams:
www.streamlines.com
this is a do-it-yourself handline for bigger lures. maybe this is exactly what you're looking for:
www.hadfield.ca/Gear/spool.html
do a google search under "cuban reel" and you'll find some interesting things. the one cuban reel i know of is made by jeros and you can get em at most wellstocked tackle shops, i think.
finally, this isn't a handline but an updated version of the Pocket Fisherman. I include it here only because it's so weird and great, both at the same time:
http://www.emmrod.com
if anyone else has any thoughts, please post em.