I am actually in the middle of finalizing a system that is the same as you described. I built a 15 gal. aluminum kettle with a 5500W 240V Camco ripple element and a toolbox control panel with all Auber parts with a 12 gallon rectangular cooler. With a PID the 5500W element works perfect. It brings 10 gallons of water from about 75 to a boil (with the lid off and and losses through the aluminum) in about an hour. And when the boil is reached I just put it into manual mode and set it at 75% output to minimize my boil-off rate.
I average about 3 degrees F of heating per minute at full power.
I plan to have a two tier system in the kitchen with the boil kettle higher than the mash tun. I will bring the sparge water to temp and then gravity feed into the mash tun. Next I will fly sparge while draining the runnings into a bottling bucket (not the one I actually use for bottling because I have read that there may be some bacteria present even after the mash). And after I have drained all of my sparge water I will transfer the wort to the boil kettle up top. I will most likely pour it for the first few batches until I decide to spend even more money on a pump. Then I will boil, cool (might need to consider a plate or counter flow chiller due to the IC and the heating element interfering), and then gravity drain to the fermenter.
This setup will allow for both fly sparging or batch sparging with 1 pump and 1 electric kettle, and with a pump and recircing you can do stepped mashes as well by adding a calculated amout of hot water. You also will not be pulling directly from the mash tun if you have a pump, so this might help prevent stuck sparges.
You could pump wort from the mash tun through the IC which could rest in the boil kettle as a sort of HERMS coil I guess. Might need to set the temp set point a degree or two higher to account for losses.
Disclaimer: My first brew like this (sans pump) is not until next week so there may be flaws in my reasoning.
Here are some pics of my setup.