Sterling Vapor sells a 3.7v passthrough - It has a 3.7v battery in line. For the 5.0v passthrough, your best bet is the Smoke tech one you found on madvapes.
As to the ego passthroughs - They are 3.2v. The "passthrough" does not bypass the battery or the regulator. They are regulated to 3.2v. Any passthrough with an inline battery is more like charging the battery while still being able to use it. In the case of the eGo's, no matter if they are plugged in or not, the voltage is regulated.
There are benefits to regulated voltage. It provides a really consistent vaping experience through pretty much the entire life of the battery. So, the vape you get when it's plugged in is the same vape you get when you're away from a power source - almost right up until the battery dies. The same goes for non-passthrough eGos - they provide a very consistent experience from the time they come off the charger until right before they die. -- In this case, it's just a little info for the thread because the OP is looking for a 5.0v and a 3.7v passthrough which the egos are not either of.