For a top box I found an army surplus aluminum box that was origionally used to house radio equiptment. It was only 10 bucks and is excellent quality.
Another option is to use one of the plastic type suitcases.Don't laugh too hard these things work and many are waterproof. I have used some samsonaite products that once the handle was removed and some decals put here and there drew some good comments. These can be picked up at thrift stores for a couple of bucks.
Panniers? Go ahead and laugh some more

but ammo boxes work great! They are a little heavier than aluminum but if the top is remade and the diagonal reinforcing piece is removed they are not too heavy. Cost?? About 20 bucks each...and totally waterproff.
If I knew how to post some pics here I would be glad to do so. If anyone wishes to have pics emailed send me an email at
cstanley@sunlink.net.
CLAUDE