I've been working with a Look 586 frame and the integrated post actually has a lot of adjustability, using all the various spacers provided. I picked up another e-Post (off eBay) that doesn't use any elastomer at all, so sits at least a full cm lower (but no doubt wouldn't offer as cushy a ride).
I also have another e-Post "R5" that uses a different mounting for the seat, which can be reversed upside down to lower the seat more than a cm. The R5 has little setback... Look also offers the R30, which has more setback but uses the same seat attachment method.
The R5 and R30 are mostly used with Look's TT and mountain bikes... but fit and work on the road frames with integrated seatpost just fine, too. I have no idea what the e-Post without any elastomer was used on originally. Maybe an earlier version of the 595.
Finally, Look also offers a "Re-Post" that's specifically for bikes which have had the seatmast cut short. It is highly adjustable, just like a standard seat post. I don't think it has the elastomers, though. I haven't used a Re-Post personally.
Park Tools makes a cutting guide. Several in fact... the largest one is what's needed for seat posts. It's made of metal. The guide that Look provides with their frames is plastic or nylon, so not as reusable.