Jean, I can't show the blade, becouse it isn't mine. If I remember correctly, I have been told it is an untypical Chenok blade from Northern Malay regions (Singora). As I said before, this sheath form is to be found also there, sometimes with coteng hilts, see Dave Henkel's site:
http://kerisarchipelago.150m.com/webpage/Tajong2.htm
Please note, the pendokok in the picture from my last post is also very similar, if not directly the same type.
As I stated in my first post, there probably are traces of rattan binding still visible on the stem, which Dan confirmed.
That's why I posted this picture as a sample how Dan's sheath most probably looked like.
Regarding the exact area, I already wrote: "Most probably Minangkabau? Not much is really known about South/Central Sumatran forms, and it seems it will for ever stay so." I don't have heard about a serious research regarding keris in these regions. As soon as we are moving out from Palembang, we don't have nothing really supported - regarding Lampung, regarding Palembang towards Pegunungan Barisan, regarding Bengkulu, regarding Indrapura, regarding Palembang towards Jambi.
Most of what we can recognize in this part of Suamtra is a changing level of Palembang influence (which is again influenced by West Java or and later Mataram) or direct West Java influence regarding Sumatran South-West coast; - interacting with Bugis influence. Whe can perhaps guess about the region using this changing level. This is better then nothing, yet not really serious.
Regarding similar sheath (and blade) style on Peninsula: keris do travel, as do the people. We know there are serious old Minangkabau populations on Peninsula, we know that Minangkabau keris was much appreciated on Peninsula, and we know about ties between Minangkabau and Peninsular royal houses. And that's unfortunately almost all.