I am in the process of ordering a KR case for my space marines, so have gotten familer with their site. No foam on hand, and I'm not an
IG player, so take this with a grain of salt...
http://www.krmulticase.com/trays.aspx?type=L&system=WH40K&army=IG&d=1
Is the KR page with the custom cut foam for the guard. IG11 looks to hold 2 tanks, a flyer, and 4
HWTs. That's pretty much everything but the troops and the
ADL. You may be able to stick the
ADL in the tank slot you are not using, I honestly can't answer that. You might want to look at the wall segments and a tank and see if they are about the same.
As IG11 is a 3/4 hight chunk of foam, you can fit a 1/4 tray on top of it. That's going to be a N4T or an M4T, depending on how tall your guys are. Or you could compromise and get one of each N4H and M4H (the half width versions).
IG11 + M4T is one of the stock
IG sets (Imperial guard set C) So you should be able to choose a case you like, ranging for card stock to aluminum, choose custom foam,
IG, set C, and be all set.
If you want a dedicated tray for your
ADL, they make one; SM36. If you go this route though, you have more then one unit (KRU) of foam, so will need to get a bigger bag/case. And then figure out what to do with all the extra space.
While I'm sure you could get a similar set up from other companies, I'm not familiar with their websites enough to make recommendations.