Is it possible to virtually vertical partition and oracle database table?
I'd imagine that having your data split across multiple tablespaces (and therefore potentially multiple disks) would improve the seek times.


Your whole premise behind the question is faulty. You do not need to split your data between tablespaces to spread the i/o across more disks, you need to increase the number of disks in your RAID10 or (better still) ASM array. You will get less performance gain, less space efficiency and far more maintenance trying to manually tune the i/o like you are suggesting.

ASM beats RAID10 primarily because it understands the data being written to it - so for example it can vary the stripe size between data blocks and logs.