is it possible? Yeah. Is it stupid? Yep. 
Would it be fucking sweet to have a lambo? Mmmhmm. Me and Onyx were just talking about the possibilities of something like this earlier today.
If you could throw down about a solid 40-50g’s, the monthly payments would be managable assuming you could get a longer term home equity loan, although you probably wouldnt really have money left over for shit else. Assuming you had your mortgage and all other living expenses to pay for as well.