Are there real lexers that use NFAs directly instead of first transforming them to DFAs? I am taking the Coursera class on compilers and in the lesson about lexers it is hinted that there is a time-space tradeoff between using non-deterministic finite automaton (NFA) and deterministic finite automaton (DFA) to parse regular expressions. If I understand correctly, the tradeoff is that a NFA is smaller, but is more time consuming to traverse because all possible states have to be regarded at the same time and therefore it is most of the time transformed into a DFA.  Are there any lexers that use NFAs instead of DFAs in "real"-life i.e. some compiler that is used in production and not a just a proof of concept?
I see only two applications of using an NFA (or rather its power automaton without writing it down) instead of a minimized DFA:


Homoiconic languages, where you may want to modify your lexer frequently
Strange syntax that may blow up your DFA like

identifier := [a-z][a-z0-9_]*
indices := [0-9_]{1,256} //up to 256 times
var := identifier "_" indices | identifier


If you take the last rule as a precedence, your lexer has to check whether an identifier contains "_" within the last 256 symbols and shorten it in this case.