Welcome!
I think the more important thing to know is what hood are you using? There are no 40" or 42" cabinets -- that's one of the things with IKEA...there are fewer options as far as cabinet sizes go, so you have to be a little creative at times. Have you considered using a hood that doesn't go inside a cabinet? A chimney style, perhaps?
IKEA no longer offers that angled corner cabinet. You could build one yourself and use the 15" IKEA glass door for a similar look. The biggest hurdle you'll have is finding ahinge that closes to a 45 degree angle instead of a 90 degree angle. Check
Rockler or
Lee Valley for specialized hinges. Constructing a cabinet out of 3/4" plywood or MDF isn't that difficult -- we made a small cabinet to house wraps and baggies, used an IKEA door tocoordinate withthe others, and painted the box to match. Birch veneer is widely available, so you shouldn't have a problem with matchingyour box. Engineering is another matter.
Off to take some pictures of the finished cabinet -- I have been lazy about it! You can see the
current state of affairs here, to be updated later this evening.
Hope that helps!
Susan