I think in BI projects we often have End-to-End methodology : kicked off with Source system(r/3 or legacy system) and ended up with Target system(BEx/webtemplates/EP)..
Full life cycle project contains a cycle where a starting point from which project was kicked off, on same point project will come to completion going via different phases and modules.
I think of Full Life Cycle as process driven: create a sales order, fill it, deliver it, bill it, receive payment, pull data into BW and check report accuracy.
I think of End-to-End as data driven: Pull all sales orders into BW, is the PSA correct? Yes-continue. Is the data as expected in the ODS? Yes-Continue. Is the data correct in the cube? yes-continue. Is the query correct? Yes - Continue. Does the Sales Order in R/3 match the Sales Order data on the Query? Yes- great, we're done!
Although, if you ask 10 people you may get 10 different answers.