Firstly, can you confirm that you are using the PPA at
https://launchpad.net/~abogani/+archive/ppa ?
Do you have both lines in your sources.list, the deb and the deb-src, ie (for 11.10):
deb http://ppa.launchpad.net/abogani/ppa/ubuntu oneiric main
deb-src http://ppa.launchpad.net/abogani/ppa/ubuntu oneiric main
If so, that should work - and does, for me.
My complete output (this was the second run of apt-get source so it had the downloads already):
chris@bun:~$ apt-get source linux-image-3.0.0-13-lowlatency-pae
Reading package lists... Done
Building dependency tree
Reading state information... Done
NOTICE: 'linux-image-3.0.0-13-lowlatency-pae' packaging is maintained in the 'Git' version control system at:
http://kernel.ubuntu.com/git-repos/abogani/ubuntu-oneiric-lowlatency.git
Skipping already downloaded file 'linux-lowlatency_3.0.0-13.21~ppa1.tar.gz'
Skipping already downloaded file 'linux-lowlatency_3.0.0-13.21~ppa1.dsc'
Need to get 0 B of source archives.
gpgv: Signature made Tue 18 Oct 2011 07:36:13 BST using DSA key ID BBA3222D
gpgv: Can't check signature: public key not found
dpkg-source: warning: failed to verify signature on ./linux-lowlatency_3.0.0-13.21~ppa1.dsc
dpkg-source: info: extracting linux-lowlatency in linux-lowlatency-3.0.0
dpkg-source: info: unpacking linux-lowlatency_3.0.0-13.21~ppa1.tar.gz
If yours is different can you paste the entire output (as an edit to your question) please?
EDIT: hmm -pae is only available in i386 (for obvious reasons of PAE not necessary on x64, are you i386? Just noticed your picked package has no -pae prefix (as neither did mine, but I'm on x64).