Nice one, likely will draw a lot of attention on the site. I've seen a ton of table saw powered sanders but don't recall a lathe being used before. I can't imagine my lathe (mini with extension) could handle it. I know I sure would love a drum sander as sanding sucks for lack of a better word.
Now this is brilliant! I am tight on space and this would be a great build to combine tools. I love the fact that you don't have to worry about the drum being centered since your using centers! I might change beef up the raise and lower rod so that there can't be a twist, but still very cool! Great Job!