Anthroman,
I think you are going to have a great adventure. Be sure to take your malaria medicine. I spent 6 months in the jungles of Thailand and even though I took Larium religously I contracted malaria 4 months after getting back in the states. I will tell you the knives I took with me and what I would change.
When I went to Thailand I took a SAK soldier, SOG tomcat, Kabar, and a spyderco sharpmaker. These knives all worked very well. I picked up a machete in country. Even though the Kabar was carbon steel I didn't really have any serious problems with rust. The leather handle did get moldy a couple of times but was easily cleaned off with no damage.
What would I change? I think you are wise to avoid military looking knives. Even though the Kabar served well I think I would leave it behind if going again.
First off I would not change my SAK soldier, unless I wanted a SAK with sissors. Don't get a SAK with "all the bells and whistles" as they get to big to easily carry and are too hard to hold.
I would take a medium sized folder with a clip instead of the SOG tomcat. Something like the Spyderco Delica or even better the Spyderco Calypso Jr. if you can find one. I would get a straight edge, but if you think you need serations no more than 50% serrated.
The next knife I would add would be a leatherman supertool. These little babies are sooo useful. Don't leave home without one. Get the supertool, it hase several useful tools, and blades and they all lock!
I would also take a dozen SAK paring knives, at $5.00 each they offer alot of cutting ability for little money. I would have kydex neck sheaths made for 2 of the SAK paring knives. These knives are so light you will hardly know they are around your neck until you need it. You can also trade some or give them away as gifts if you need to.
I would also take one or two carbon steel Frosts with the red/black injection molded handle. I would get custom kydex sheaths for these as the sheaths that come with them are not so good. At approx. $10.00 you have to cut costs somewhere. Get the sheaths with tec-loks and you can remove them when needed and wear around your neck if desired as these knives are very light weight also.
I would take a spyderco sharpmaker and a DMT double sided diamond folding hones. I would get the one with fine grit on one side and coarse grit on the other side. These two items will keep all of your knives cutting well, with the exception of your machete. When you buy your machete buy a small file to keep it sharp.
I would also buy a small climbing type backpack to take along, and one or two led flashlights. I took along a very expensive water filter and never used it. We cought water off the roofs of our huts for drinking. I would also put together a compact medical kit to take along. I would include water purification tablets, immodium AD, tylenol, ibuprofen, bandaids, steristrips, silk medical tape, small amount of duct tape, neosporine ointment, benadryl, and any perscription medications that you take. A couple of jars of peanut butter will go a long way. I would also take as many long paperback books as I could. One year is a long time and jungle time is at different "slower" pace. I would also arange for some friends/family to send you some care packages every couple of months. Trail mix with m&ms, batteries, more reading matterial and news from the states will be appreciated. Culture shock is for real. You will get it twice, the first time will be when you go to the jungle, the second time will be when you go back home after a year. Have fun and be safe. Sorry to ramble so long.
Tom