if they are true sith then they are not force users like palp and Exar so that would be pretty weak. it could be the vong, obsidian can bring them into the fold. i know like you said that the maverick jedi were the ones who, along with the interbreeding of the sith, created the "sith lords" like ragnos but an explaination of the vong could be interesting. the vong are from the unknown regions and canderious was talking about them in K1 (random convo?), so it could fit with KOTOR. plus they were once force users then they cast themselves from the force. its all fresh to SW and it would fit nicely in the canon that has become SW EU.