I did this today with my 488RC4 brackets. Works great.

http://www.diyphotography.net/diy-l-plate-l-bracket

That's pretty cool. Just paint it black or something and round off the corner and you're set.

nice DIY. Yeah, L-brackets are expensive, but once you've used them, you'll see how nice they are. This mod will work, but once you've seen the details on the custom made brackets, you'll appreciate them much more.

Cool idea, but I think the Bogen plates are bulky by themselves. I don't think I'd like another piece of angle on there too.

That said, why doesn't anyone make custom L-brackets for Bogen heads?

I shot with it for 2 hours or so this morning. It didn't feel bulky at all and it works awesome. I wish Bogen made a custom plate, but really this works just fine.