So, here's my suggestion. :) A decent grid tool with abilies like custom square size, line color. Maybe some options to draw a smaller sized grid instead of a fullscreen one..Well well.. This would absolutly make my day/week/month and I am sure others have been thinking about this themself when trying to align things on the screen.
And if i've somehow missed an addon (been looking at the bigger addon sites) that does all this..feel free to point me in the right direction :D
Honestly I'd rather see a mod using phLayout (might not be the exact name) to be able to extrude the edge of a frame into a line, allowing me to place a frame on that line and slide it out to the desired point and know that the two frames are aligned.