A lot going on in your comment so let's hit the points one by one...
1. I have used a Smart Keyboard Folio for years. At first I hated the typing action but in time I grew used to it, I feel the key action is "ok" for the most part. It isn't great. I'm not sure getting it to light up as designed would be possible.
2. I too was hoping for everything you were but I think the best we could have hoped for to get close to your suggestion is the way the Surface Pro thin keyboard is designed. It has real keys, maybe not great ones like the Magic Keyboard, but maybe halfway between the MK and Smart Keyboard. It also has a trackpad, is thin, and folds behind the Surface tablet. How does it do this? Well it magnetically hinges to the front bottom lip of the Surface so it sticks out further and the Surface itself stands using an integrated fold out stand. Works ok but kickstands suck for your lap. I don't see a way you can make a design like this using the iPad as currently designed, it would require a new iPad design and major rethink. Look at a Smart Folio, when it slots into a lip there is no room to add space for a trackpad, it won't fit in the size constraint of the dimensions of the case. It MUST float up to work like the MK and to float up it pushes the iPad back and further from the keys and trackpad. This changes the entire center of gravity and makes it very top heavy and would tip something light like a Smart Folio right over, hence the added weight. You also need added weight to provide strength and rigidity to the magnetic attachment and hinge... if that wasn't ROCK solid a lot of $1000+ iPads would be crashing to the ground right about now.
3. Basically Apple had to make a choice... they couldn't fit a trackpad into a Smart Folio like keyboard so they decided to just keep both and let you choose. If light weight and folding the case back on itself is the priority then you must choose the Smart Folio and when you need to do a heavy amount of typing you could always pair it with a Magic Trackpad or a small bluetooth mouse which are fairly easy to bring when traveling. If on the other hand you mainly extensively use your iPad for typing, typing, and more typing OR you mostly use your iPad at home the MK is probably fairly ideal. You get a world class keyboard, backlighting, and adjustable screen tilt with an always available built in trackpad and when you need to use the iPad as a tablet on lesser occasions you can just pull it off and leave the keyboard behind on your desk. Likely fairly safe at home.
There is no one way to have it all... the closest to what you describe again is the surface pro keyboard and i encourage you to check it out, but it is a master of none... it still isn't a great keyboard to type on, i don't think it is backlight, its a bit heavier than the smart folio keyboard BUT it is still much lighter than MK, folds back on itself, and has a trackpad. to do it though and make on like that for the iPad would require a significant redesign of the iPad including an integrated kickstand to the iPad, which of course then makes the iPad thicker and heavier too...
This is why Apple and their engineers get paid the big bucks... to try to solve these impossible problems, and for now this is the best answer...