I totally agree, plus it's a pretty hefty project so that much time is needed. I know we are doing the portrait walls, floating corpsed pumpkins, candles, etc. If I can im going to try and make the gargoyles to hold my flame cauldrons and a couple dementors. I started a thread back in 2013 that has some of my ideas, if memory serves me I posted a monster book how to on there and the gal that made it also made a Dobby and loads of other cool stuff...I believe her name was Katster on here.
Also if u go to pinterest, see signature, I have 2 HP boards...titled Halloween...Deathly hallows (tons of ideas and diys)...and the 2nd board Deathly Hallows 2 (has pictures I think will work for a portrait wall (some r HP others just similar styling).