If that wasn't the most laborious encumbrance pun you've ever read, then I simply didn't try hard enough.
Anyhow, I've worked out a system (borrowing liberally from the idea that I first read about on Delta's Site for using the stone as a system of measurement) and tweaking it for my purposes...
You can carry your strength score in tenweight units. A tenweight is a measure of about ten pounds. When determining encumbrance, use the following generalizations:
· A suit of light armor weighs 1 tenweight.
· A suit of medium armor weighs 2 tenweight.
· A suit of heavy armor weighs 3 tenweight.
· Your basic gear typically weighs 1 tenweight; if you carry an exceptional amount of gear, count it as 2 tenweight.
· Your weapons (including ammunition) have a general weight equal to their total dice divided by 10 (rounded off normally). If you carry two daggers (1d4 each), a short bow (1d6) and a two-handed sword (1d10), you carry 24 dice of weapons; count this as 2 tenweight.
· For every 100 coins you carry, add +1 tenweight to your encumbrance (coins are fairly heavy).
Each time you surpass your STR score in tenweight units, decrease your move by -10. With STR 7, you can wear chainmail armor (2 tenweight), basic gear (1 tenweight), a mace and sling w/20 sling stones (1 tenweight) and 300 coins (3 tenweight) without being encumbered (you are carrying 7 tenweight: your STR score). You can carry from 100 to 700 more coins (bringing your total encumbrance to from 8 to 14 tenweight) and take -10 to move. If your total encumbrance increases to anywhere from 15-21 (you start carrying around a chest with 1400 coins inside), take -20 to move.
While this requires a little bit of book keeping, it can easily be adjudicated on the fly, and doesn't require you to count every piece of gear. If you are one of those players who jams every conceivable item into your backpack, then the GM can just decide you carry 2 tenweight (or heck, even 3) of gear, and call it a day.