Eugh. The very concept riles me. It's a "let another's lips praise you, and not your own" issue to me. Having a baby named after you should be an unexpected tribute
by someone else due to your great personal awesomeness... not something you get to decide
yourself to do because you get a kick out of it. It seems to me to be along the same continuum as making a Wikipedia page about yourself. If you're worthy, someone else will do it for you... if they don't, you're probably less awesome than you think.

Also, yes, MIGHTY practical issues.
And it peeves me that 99% of the time it's men who want Jrs, not women (Gilmore Girls aside!).
DD does have the same middle name as me, but only because a) it's been a family name for 4 generations - five now! - and b) I like it a lot. In fact, if it weren't a family name I might have used it for a first name. Also, DH didn't mind. If this baby's a boy I wouldn't mind using my father's first name as a middle name (David), but... he'd never ASK me to do that. I was a bit offended when FIL jokingly suggested we use his first name.