My 2Dtools contains a Fillet/Chamfer tool, with the radius set to 0 it trims/extends the two selected intersecting edges rather than fillet/chamfer them... In fact using AutoCAD's Fillet tool with a 0 radius is a way of doing the same thing.
2Dtools also has 'Adjust' which lets you select sets of edges to trim/extend to and then sets of edges to 'adjust', you can pick individually or use a 'wiping action' to do multiples...