Thanks to packer0440 and this thread, I was finally able to find the oil pressure sensor on my 1993 K2500 Suburban. The location of the oil pressure sensor on the 454 TBI / 7.4L GMT400 is indeed in FRONT on the engine on the driver side, not near the distributor.
On the 1993 Suburban 454 it is easy to find once you know where to look - in front.
I used GM Oil Pressure Sensor part 19244500, and Lisle 13250 Oil Pressure Switch Socket.
My switch was actually physically broken and leaking oil in addition to sending erratic readings. It also kept the fuel pump running nonstop even when the car was off. This is how we figured out it wasn't working right.
* posting this for the next person who can't find the location of the oil pressure sensor on the 454 *