Is there a tablet keyboard that you can actually use in your lap? I've always hated the top-heavy weight distribution of tablet-keyboard combos, which is the number one reason I prefer laptops for any extended typing.
I usually show someone something with it open just sitting in my hand grabbing it at the side, like you would a laptop
If you're looking for an iPad keyboard that's very bottom heavy to counteract the weight of the iPad, check out the BrydgeAir. We'll be sharing a review of it in a couple weeks (I'm actually going to be sharing several keyboard reviews). It's machined from a single piece of aluminum and it weighs over a pound (520g vs 437g for iPad Air 2). I can use it comfortably in my lap with no hard surface for it to rest on. ClamCase Pro (as Jessica mentioned) is also comfortable in a lap.