I do realize how much safer it is to rf and I really regret not being able to at the moment. Sadly, I think I could safely say all of the other moms that I know dont rf their toddlers by choice though, not necessity, how common is it really to continue to rf after the first year? I showed my husband and mother-in-law articles on it and they didnt find it to be a huge deal either...
I don't know any other parents in real life who RF either, with the exception of my two daycare parents... who do it because I said they should, lol. (They do know why, it's not just blind faith, but they trust me pretty implicitly so if I say stay RF, they stay RF.)
Unfortunately it's not common to continue RFing after the first year. That's something that I would imagine everyone on this board would like to see change... and very, very slowly -- one parent at a time -- progress is being made. I'm one of those "converted," barely a year ago my kids did not have the benefit of the knowledge I now have (from this board and later my tech class.) I think part of the reason I'm so passionate about it is that people just don't know; if they are aware of it and don't find it to be a "huge deal" then I think in most cases they don't understand all of the "pieces," so to speak. They don't understand that putting kids in the car is the most dangerous thing we do with them; they don't understand WHY you should RF, the anatomy and physics of it; they don't understand what can happen to a FFing child vs a RFing child in that same collision.
RF is not a magic pill, it will not save every child in every crash, but it is a tool that we can use to make our kids that much safer while they are doing the most dangerous thing that they will do for the next three decades. For that, I'm willing to be the odd one out, and I'm willing to preach on it online and in real life, and I'm willing to not really care what other people think. (I mean... when you pile six kids out of an SUV you get weird looks already, so why add the fact that your three year old is sitting backwards, lol!)
If you can, I'd show your DH Joel's Journey, the video on youtube narrated by his grandfather. (Youtube doesn't work on this computer or else I'd link it.) That video is the one that affects me the most, personally, and reminds me why I bother on days when it just feels like too much hassle. If you can get him on your side, MIL may be easier to convince.
FWIW, the MyRide, TrueFit and Complete Air all tend to install with a fairly small amount of front-to-back room. If you can't get your Boulevard to work, you could try those.
And I second Wendy's suggestion of finding a tech (preferably one from this board, who won't act like you're nuts for ERFing) to help you get a good, upright install. Not sure where you are, but chances are we have someone close.