I am sorry that the epson 8100 didn't work out for you, I remember how excited you were when you first got it. Hopefully you will sell at and not take a loss on it, with 2 bulbs, should be cool.
I think you laid it out really good, what you just wrote, so , I'm sure the guys will figure out something for you. I am thinking you might have to move up to the 1300 dollar and above models. You got spoiled with lens shift, you might have to loosen up a little on that feature if you are going DLP, and do some physical placement yourself.
Or get a model with lens shift.
I'm sure you looked at coderguys post, he has the coderguy top picks link in his sig , maybe look at that, and projectorreviews 2012 round up for ideas, combining the 2 sources should start you on models that might do it for you. I know the pro8200 could do 110 inch screen size no problems but it sounds like you need higher grade PJ from what you are saying. I had nothing to go by in the past, so the pro8200 is kick ass for me, Love it, and I did pick it up for 659 new last dec. , so the price was right, maybe with your epson8100 your standards got raised, but coderguy who has super high standards thinks the pro8200 for the price he paid for it super good deal too.
It comes down to can the hc4000 do a 110-120 screen with the brightness and blackness that would work for you in that room, if the epson8100 couldn't do it. Did you check the lumen comparision between epson8100 and hc4000? Maybe go into the hc4000 forum and ask those guys, or coderguy might know from the top of his head. He probably does.
p.s. crap, I just checked the epson8100 is 1800 lumens, and in review on projectorreviews says it should do 110 in bright mode, no problems. Do you think your PJ is working right? Did you call epson or check in your epson8100 forum room. Maybe you need to exchange it, I don't know. You got 2 year warranty and what do you have to lose , if you were planning to sell it anyway? If your warranty is not tied to your name, when you sell it can the other person keep the rest of the warranty? I don't know about that, either? If the warranty is tied to you, what do you have to lose calling epson and exchanging it, right? Unless you already tried that already. ... oh yeah, you had the motion effect problem too, unless that is malfunction too.
I've had my pro8200 on all day, 8 hours or more, I don't think you could do that with the epson8100, from what I remember reading in forum rooms. Maybe get cheap and good PJ from amazon and if it sucks for you, return it. It is your cheapest solution, and give it a few weeks to figure it out, it took me a few weeks to get it down. And 7 months until I moved back a few feet and got the "kick ass" feeling flying jets in battlefield 3.
You were used to 10 hours a week with your epson8100, but with the pro8200, you could kick the stuffing out if it, coderguy and I am, and it keeps on ticking.