For right around the price of the Letus you can get a camera like the D90 or Panasonic Digix DMC-GH1. In terms of shooting your video, you'll be getting a much simpler process. I've found the 35mm adapters I've used (granted many home made, but still with the Redrock as well) to be somewhat cumbersome, and always a bit finicky.
With these two DSLRs you can shoot HD video and get tremendous depth of field and selective focus control. Plus you can interchange lenses for even more flexibiltiy. I really enjoy my Panny GH1. Also, for a bit more (about $2000 with lens) you can get the Canon 7D which has slightly better image quality. All of these shoot in 24p as an option too, if you ever find yourself wanting to add the progressive 'film' look to your video.
After owning adapters and then the D90 and now the GH1 I would very much recommend a DSLR.
I guess I should point out that this is also assuming that you have the software and computer horsepower to edit AVCHD. The format can be cumbersome to edit.
All that said, if you're looking for DoF control and your tired of getting far away from your subject and zooming in (or find yourself in situations where that isn't an option) then an adapter can be a fun toy and a useful tool.
