The decision coming out of the UDS-Q kernel meeting in Oakland on Monday was "Definitely go with 3.5, and tentatively look to 3.6. Will re-evaluate at the time 3.5 releases." With this being a non-LTS release, hopefully they will be aggressive and go with the Linux 3.6 kernel.
The Ubuntu 12.04.0 LTS kernel is shipping with Linux 3.2.
In semi-related news, there was also talk about Xen virtualization in Ubuntu 12.10 (notes). Xen 4.2 is being targeted for this October Ubuntu release with the xl tool-stack, support for Intel Supervisor Mode Execution Protection, PCI pass-through for Linux guests, EFI support, and documentation improvements. From Ubuntu 12.04 I have done AMD/Intel KVM vs. Xen virtualization benchmarks.