I have a Joes Racing inline temperature sender adapter. This allows you to hook a 10an line on each end and put a 1/2" npt temp sender in the middle. This allows you to take temps on the way back from an oil cooler, etc (which is exactly what I was going to do with it). This is still new in the box and factory sealed. It's also designed so you can bolt it in place (1/4" bolts as I remember) so it's not hanging on your hose.

$45 + freight