After examining my army list, I decided to go all out and have 3 Land Raiders. To squeeze in the third Land Raider, however, that required dropping the Assault Terminators. This actually turned out in my favor as I could then turn them into Sanguinary Priest models.
The power sword I made using plasticard for the blade and chopping the thunder hammer top half off and removing the wires to the arm.
The hip pieces are made using melta bombs sanded down and cut in half. I also chopped the claws from the left hand, all except the bottom one.
Finally, the light at the top was put together using the top half of the hammer, chopped the square section off and added a light from that weird little generator thing (what is that thing?) which came with the assault Terminator sprue.
So there we go, some nice and quick Sanguinary Priests (or really the equivalent) without spending $25 for each of them. Hopefully I'll have some time to paint one of the Mk1 Landraiders for next Monday, though with Skyrim in my possession, that may be hard to do!