Shot some stuff in 720 30P HDV and converted to 24P in FCP and
then back to 30P to maintain 24P look.

Anyone else have some work on this process?

That probably doesn't work very well. FCP doesn't do a good 60i to 24p conversion much less a 30p to 24p which takes very expensive equipment/software to interpolate frames and make up new frames.

I suggest you shoot and edit in 24p because of the many benefits (space, better compression, etc.) But if you need a 30p timeline to mix in other material, shoot 24p and do a 3:2 pulldown using DVFilm Maker. http://www.dvfilm.com/maker/index.htm

Whatever you do, don't keep doing the workflow you mentioned. Sooner or later you'll see it looks silly. ;-)