[supafamous]

If you're planning on building in Vancouver you'll have a very hard time finding a lot big enough for what you want. The FSR (Floor Space Ratio) for a RS-1 (standard lot) is .7 meaning you can build up to 70% of the total lot size. For example on a regular 33x122 lot you can build about 2800sf. You need a 50x120 (6000sf) lot to build around what you need and those are very hard to come by - if you're looking in East Van figure a cost of $1.8-2M for the lot. Use Zealty.ca to look at listings by lot size.

Building cost wise you can go as low as $700K to build 4500sf but that's pretty low end work. For a custom home figure $250-270/sf in Vancouver.

I've been looking into building a duplex in East Van for a while now - just trying to get all the pieces to fall into place (money, partner etc). Feel free to DM me with your questions.