There was talk of Ducati doing a 1080 cc big bore version of the testastretta (or it could be a big stroke version since the bore is already 100mm). In the same article it mentioned that JHP have already done a 1080 conversion. They certainly have with the 992cc Dual Spark two valver that currently powers the Monster 1000, 1000 SS and Mutistrada, both JHP and Sigma do 1080 conversions.
I found
THIS bore and stroke calculator for most of Ducatis engines so it gives some idea of what might be possible with a bit of mix and match
[Edited on 31-5-2005 by Jools]