Just some thoughts off the top of my head.
Have you thought about setting up tool pallettes to hold your blocks? Then you could just drag and drop.
If these are blocks that you always use, and there's only 50, you could load all of them into your default drawing template. Then every time you start a new drawing, your blocks would be there.
If you're using 2006 you could create dynamic blocks and merge some of your blocks together and cut down on the number of references.