Create hot "sauce" from capsaicin extract
There's no point in getting pure capsaicin and diluting it yourself when you can buy capsaicin in just about any strength you want with all the work done for you. If you want something truly, painfully hot then get capsaicin 1 mil and then measure it into your dishes with an eye dropper. Be real careful with it, use gloves and don't sniff it, even at 1M it can still seriously hurt you. 

I second @Jolenealaska's warning that pure capsaicin is dangerous. In fact, you should not try to get the pure stuff even if it is available, get something somewhat diluted as it is safer and easier to work with. Pure capsaicin is used in industrial applications, you need to work in tiny quantities, requiring special equipment. It can also put you in the hospital, so just don't do it. As cool as it sounds "I made this sauce using pure capsaicin!", the reality is somewhat different.