Hi Jim,
This article (limited as it is,
http://en.wikipedia.org/wiki/Hadendoa) indicates that the Hadendoa are a sub-tribe of the larger Beja ethnic group, sharing the same language. Perhaps what we call Beja daggers could be better identified as Adabde, Hadendoa, Bisharin, etc... according to the specific sub-groups.
I could also see the chilanum as an inspiration for these hilts. Then again there are so many variations of I-hilts in Eastern Africa that it could very well be a local development.
All the best,
Eamnuel