Has anyone tried to incorporate different ideas (scrum, six sigma, pmp, lean?)
Essentially all of the above derive from the Japanese Quality Movement in the early 1980's.
It's all about increasing quality by reducing waste, called Muda in Japan
Lean was Toyota's implementation of the Quality Philiosohies
and Six Sigma was General Electric's attempt to Americanize Lean based on corporate culture of the day.
Fast forward 20 years and the IT industry have realised that all this 'lean' thinking is a great idea for building better quality software, faster. In what has been labelled Agile.
XP (extreme programming) and SCRUM are just two different implementations of Agile techniques.
Tradiational management and software management is coming up against these new ways of thinking.
You can't have it all. Either your focus is on command and heirachy (DO AS YOUR TOLD, traditional approach) vs Collaboration and working together to reduce wastes and deliver amazing things to customers (LETS DO IT TOGETHER, new model).
If you want to go deeper on this, the best approach is to read back on the original LEAN philosophies and then see how you think they can best be applied to project management. Many of best project management ideas were already considered as part of the original lean movement, read the book 'The Toyota Way' and look into lean that is where you can find your own answers.
Google: the seven types of muda for a start.