Solaris 8 Migration Assistant 1.0
Update 4 of Solaris 10 gives us the second type of branded zone : one that allows you to run your old applications using Solaris 8 on a brand new machine running S10, either because you want to have them run on better/newer machines, either because of support reasons. ( or because you want to DTrace it 
. Seems that lots of customers are still quite happy with Solaris 8 and legacy apps.
This feature comes with an extra download but it doesn’t come for free, although you can get an evaluation version here.
There is also a FAQ available on the product.