This has come up before in a somewhat similar situation (see link below). First question is what you want above the hood. If I read you correctly, you have upper cabinets on either side of the range, but no cabinet actually above the range. This is where I presume you will build your custom stucco enclosure.

The reason this is important is because it determines how you will "back vent." What I think you mean is that you need to vent horizontally. The term back venting is often used to describe a vent that vents straight back, so that there is no ductwork at all above the hood itself. This is generally true for true undercabinet hoods that mount to the underside of a cabinet immediately above the range.

If however you have nothing above, then you can use any hood liner that can vent up and then horizontally out. Essentially any custom hood liner can do this, using either a blower mounted in the hood, or if you want a quieter vent, then using a remote blower located on the external wall where your ductwork will exit your house. There are many sources for such liners.

Monogram is not typically thought of as a "top performer" for ventilation. With the uncertainty over GE Appliances now, I'd be even less inclined to use them. Do search this forum: there is lots of great information on hood vent companies. Some of the companies that get positive feedback here include Vent A Hood, Prestige, Independent, Modern Aire, Wolf and Broan.

Other misc thoughts: Do you have exactly 36'' to work with in width? If so, then you will need a hood liner that is even narrower than 36'' to fit inside your custom enclosure, which would be limited to 36''. In that case your vent size is even smaller, and even 36'' is marginal for ventilation performance, as the usual recommendation is at least 3'' wider on each side than your range. You might compensate at least partially by choosing a hood that is deeper than usual, as long as it doesn't bump anyone's head.

And, if you truly have to use a hood vent that back vents without any ducting above the hood, look at the VAH SLH-6.

Here is a link that might be useful: hood vent thread

Thank you for your thoughtful response. My problem seems to be that all of the hoods need to go UP for 1 or 2 feet before they can turn 90 degrees to go out horizontally, and they seem to need more height than I have to do so. Also, I was hoping for 32" to 34" inches above cooktop height, and many spec out maximum 30", which would be a headbanger for my husband.

I agree with clinresga's misc thoughts...If you're hood isn't big enough, you'll have some vapors escape. Those escaped vapors will deposit a grease film on your kitchen, particuarly the hood exterior. With stucco, it will be hard to clean that grease off, so it's EXTRA important that nothing escapes.

astridh:
Everything is a tradeoff with vents. Purely from performance standpoing, we'd all be using vents that are at least 6'' wider than our ranges, at least 27'' deep, mounted no more than 30'' above the range (and forget the island mounting option!). Of course in the real world we all make compromises. Remember that ventilation needs may also change depending on how you cook. If you love to sear over high heat, like I do, or stir fry, then more ventilation is better--thus our specs for new hood liner, which will be 60'' over a 55'' Lacanche, with a remote 1200 cfm FanTech blower and silencer venting vertically through 10'' ductwork.

If you are less likely to make smoke, and are OK with the notion that once in a while you'll have smoke spillover, then you will be fine. Do agree with alku05 that grease on stucco may be a consideration.

So...you're already compromising by using a relatively narrow 36'' hood over the 36'' range. You could mount 36'' above the range but will suffer further loss of efficiency. Depth of the liner also is a factor: going with a deeper vent, say 27'' instead of 24'', would help, although you need to spec out the hubby head impact issue.

But, back to your issue--I think there are many more options than you think. For example, Modern Aire's website states that their custom hood liners can rear vent as long as they are at least 14'' in height, which you should have plenty of room to do
Modern Aire insert specs
My best advice would be to contact one of the highly rated custom liner manufacturers directly. They are typically very helpful and can really figure out what you need in a custom liner.

I assume your cabinet maker is fabbing your stucco enclosure? See Metallo Arts for some absolutely wild enclosures
Metallo Arts website

Have fun and post more questions as they arise.

Thanks for your replies. I do plan to vent up and then out the back; I just don't have a lot of room to do it.

I would also prefer to have a baffle filter rather than mesh; I have heard that they are quieter and more efficient. I have space for a maximum 8" duct.

I will be calling Modern Aire on Monday. I live in California, and they might have just what I need. I'll look into Independent as well.

Here are the brands I have checked out so far: Kobe (maximum 30" above cooktop), Best by Broan (max 30"), Viking Pro (even mounted 30" above cooktop needs 3" more height than I have, I wonder if I could just shorten the upward venting part from 12" to 9"?), Wolf (10" duct), Thermador (6" duct, has mesh but baffle accessory available, might be an option), Kitchenaid (max 30"), Prestige (not available in California, no local dealers, might buy it online but might be hard to have it repaired)

Thanks for your helpful replies.

One nice aspect about the Monogram custom hoods is that they have a unique design that allows them to be installed and removed from below. The benefit is that if the hood should ever require service it can be done without having to remove the stucco canopy.

I didn't know that. Sounds like that could be a useful feature. Thanks.