The Article on the frontpage about Google Code of Summer might answer your question. I quote :
This year we're building on previous years' work in a number of ways. Importantly we will be porting the existing LimeSurvey 1 codebase into a modern MVC PHP framework called CodeIgniter. We'll be using the lessons learned (and large quantity of coding done) from our LimeSurvey 2 developments in previous years. We hope the outcome of our 2011 program will be a big step towards merging the LimeSurvey 1 codebase with the principles of LimeSurvey 2.
Since LS1.91+ is already theres LS 2.0 isn't far away in terms of numbers.
In terms of coding hours it might take a bit longer
Since I am not part of the developer team you might post the link to this thread into the Limesurvey chat. A developer might find time to answer.