Not long ago we (Alec, Kim and me) were talking about growing single wall carbon nanotubes (aka SWNT) with different patterns on the same tube. This would bring additional coverage of the absorption spectrum since slight changes on the width and chirality rewards you with a different absorption band.
We know that a slightly different approach appeared in Nano Letters earlier this year where Jessica Trancik (that's her photo on the left) introduces defects to the CNTs with ozone and achieves good catalytic activity on I3- reduction comparable to platinum systems.
Though not a new thing, we started growing carbon nanotubes (single wall!) on 4 nm magnetite nanocrystals. Varying the catalyst size could mean diversifying the product and we're giving it a serious try.
There's only so much more to do with SWNT if only things can happen as you wish..