I have a spreadsheet that may be of use, although it has many bells and whistles. I use it for all types of traveling (business trips, car camping, vacations, etc.), so you may want to trim it down (a lot!) for pure backpacking use.
--You can store separate lists and recall them as needed (copy-and-paste).
--You can compare two similar lists and see the change in overall weight, and more usefully, see the difference as a percentage (Sure your new LMF Spork saves 3 oz., but the overall change is only 0.8% -- maybe it's time to take a hard look elsewhere on the list!).
--Weights are entered in lbs.-oz. format (2-4.25 or 0-36.25), and converted to dec. lbs., and g. Totals and Subtotals are displayed in lbs., oz., and g, and Grand Totals are displayed in lbs. and kg. (Sorry, there's no direct entry in kg or g.)
--Items change color when flagged: black when included (y), light blue when excluded (n), and orange when "maybe" (m).
--You can hide items globally that are excluded (n) and sort the items alphabetically (once your list is set) for compact printing and easier reading.
--The printed version uses two columns, Going and Coming, to act as checkboxes for items as they go into (or come out of when home) the pack (or suitcase).
--Subtotals are provided for each category, although the categories I've chosen don't necessary conform to a BPL standard (the spreadsheet predates my association with BPL by a few years).
--The XLS file works bidirectionally with Documents-to-Go, so you can edit the list on your PDA while hiking (just kidding) or daydreaming in airport lounges.
--You can export the finished list to BrainForest (an outliner for Palm OS) to create a nifty checklist, if that's your thing (and you have a Palm OS device with BrainForest).
--Pack weight, weight of consumables, weight worn, and total weight are always displayed at the top.
--Items within each category are graphed, but I admit this feature is mostly useless (and was replaced with the percentage comparison page).
--There's a primitive food calculator based on the no. of days, but you can edit the formulas (and of course delete or add rows) to your own requirements.
--And in a show of utter anal-retentiveness, there's a column where you can flag items as "Pack" (can go into the pack now), "Find" (run around on the morning of the trip and shove in the pack any-which-way), and "Carry-on" (for airplane trips). Note: these flags are not synched with the lists, so when you paste-in a list from the "library," you'll have to update these flags again.
PM me if interested (expect a response tonight, I'm on the East Coast). I think I have an older PDF version in my Profile if you want to take a look.