All slums in Mumbai have been "regularized" by Congress governments... so no question of grabbing public land by joining BJP... :-)
All you need is to board a train (preferably without buying a ticket) to Mumbai... .land there, and build a shanty.... Secular forces will subsequently ensure that you can get a 300 sq ft flat, which of course you sell at 10,20, 30 Lacs depending upon location... and move on towards bigger better things... oops.. bigger better shanties.. :-)
Anyone raising concerns on the pressure on civic infrastructure -- you refer them to Lalu, Abu Azmi etc... they'll come and perform the last rites of civic administration... :-)