I think that, if proper precautions are taken, you can safely store your bike in your basement and not have any smells. I base this off of friends that store lawn and garden equipment, boats, bikes and ATVs for years without any problems.
OK....maybe they were just lucky and who are any of us to be giving you advice on your safety? Seriously, I would contact my local fire department and ask them. Many will send someone out to advise you....for free! Be prepared though, some cities have ordinances against storing vehicles in living areas.
FWIW, to me, taping the gas cap is a waste since our cap seals quite well and the tape is going to be a pain to remove after many months. There is a vent line that feeds out the bottom of the bike anyway.