Alrighty, the title should say it all, but here's why.

Main reason i'm trying to do this is because i want to create an action that would allow one to select a folder with a large number of randomly sized files and apply a circular or square logo (in a PS layer set) to the lower-right corner and space it away from the edges. There should be a way to do this without needing a different sized logo file for differently sized photos.

the only way i can think of to use one PS layer set with a single logo size for scaling is to somehow create an action that can resize a layer set to match either a larger or smaller canvas while constraining proportions of that layer set.

Attached is an inset of an 8"x8" layer set at 600 dpi with a logo in the lower right corner. The bottom layer is a 50% gray Overlay and the Logo has a drop shadow applied. The idea is to get this file to work with any image size/resolution.
http://www.retouchpro.com/forums/attachment.php?attachmentid=23477

My fingers are now crossed.

one of the developers on the adobe forums said all i gotta do is create a *.pdp file and use the File>place command to import an image that is larger than any canvas i plan on using. Since most of the canvases that i will print are no larger than 13"-narrow @300dpi, i just made an 8x8@600 dpi transparent canvas with my logo on it, and import using "Place..." and then finish it off by applying actions that will align it properly in the corner, give it a drop shadow and PRESTO! Too easy!

SPREAD THE WORD!!!