Are there any android tablets upon which I can get smartphone service; and if so, which ones are they?
When you say "smartphone services", I assume you mean has a cellular radio, takes a SIM, connects to a carrier and can make phone calls as well as cellular data, and it not just WiFi only. There's many tablets that can do that, although you might have to use a Bluetooth headset for the phone calls with some makes and models.
Tablets seem to be so much more inexpensive than smartphones, per se.
Not necessarily, in fact the only two manufacturers that come to mind for that are Apple and Samsung. In that the iPhones seem to have a significant price premium over the iPads and the iPod Touches, all using iOS. Same thing with the flagship Samsung phones like the S5 and Note 3, they seem to have a price premium over their Tab cousins.
Is there really such a thing as a phablet other than the Samsung Galaxy Note?
"phablet" I think it really just a slang term for any phone that's larger than around 5 inches. And there's plenty of them besides the Note. I got a "phablet" myself, an Oppo Find 7a, which is 5.7 inches. And there's plenty larger than that, like the Samsung Mega 6.3, some go right up-to around 8-9 inches now, and are still sold as phones by carriers. Hisense, Lenovo Coolpad, Haier, etc. makes them. You can hold these giants to your ear and make phone calls in the normal way, and don't have to use a headset.
