After Malcom's excellent Tékumel thread I went hunting around the internet for more info about the various systems. While digging though blogs and fansites, I discovered a plethora of "alternate systems" for the setting. A bunch of them are just D&D or Runequest hacks, nothing fancy. But then I found this: Kashtlanmüyal
Now, this is a super short text but there are a few things about it that make it look like the lovechild of various games. For example, Marksmanship works like obstacle factoring in BW, armour also works similarly to BW. The reward mechanism gives character "Luck points" for stuff like fulfilling vows which is reminiscent of various things. Melee combat (and skill use) is fate-based resolution like in Amber but also reminds me a lot of the possible skill system for 5E that Mearls was musing about in his column.
This was published in 1995. I don't know who the author is but it's a pretty interesting set of mechanics that I would have sword were inspired by newer games if I didn't see the date (Amber predates it a lot however). It's not really a system imo, as there is very little currency going around, if at all, no interlocking mechanics. But I still find it to be a little gem. Just wanted to share it.