From the archives, we see that proposals for LRT in Hennepin County are not new, This 1988 document (PDF) has maps of the  Comprehensive LRT System Plan for Hennepin County

. The debate about the location of the Southwest and Northwest corridors as they approach downtown remains alive. [This mostly about whether to speed the commute of suburbanites or serve the needs of local Minneapolis residents.] The South corridor has become Freeway BRT. The priorities of which gets done first and second have changed, but the main part of the corridors are unchanged. Of course only a the Hiawatha line was done within the 20 year life of the plan. Some more discussion at City Pages.
I am still looking for a digital version of 1970s “Regional Fixed Guideway Study” proposing a 37 mile transit system for Twin Cities. Anyone have scan/map?
(Other cool documents here). Also AJ Froggie’s site.