I put this PPA together for my own use. Please view this as a stopgap until an official PPA is available. No idea how much traffic this may generate. If traffic is low/cheap I'll keep this going.

$ sudo add-apt-repository 'deb https://mslinn-ppa.s3.amazonaws.com stable main'
$ sudo apt-get update

Now you can verify that the correct version will be installed like this:

$ sudo apt-cache policy pound
  Installed: (none)
  Candidate: 2.7f-0ubuntu1
  Version table:
     2.7f-0ubuntu1 0
        500 http://mslinn-ppa.s3.amazonaws.com/ stable/main amd64 Packages
     2.6-3 0
        500 http://mirrors.digitalocean.com/ubuntu/ trusty/universe amd64 Packages

Now install Pound 2.7f. You will be asked if you wish to install without verification. Answer with y.

$ sudo apt-get install pound
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
0 upgraded, 1 newly installed, 0 to remove and 6 not upgraded.
Need to get 105 kB of archives.
After this operation, 239 kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
Install these packages without verification? [y/N] y
Get:1 http://mslinn-ppa.s3.amazonaws.com/ stable/main pound amd64 2.7f-0ubuntu1 [105 kB]
Fetched 105 kB in 0s (527 kB/s)
Selecting previously unselected package pound.
(Reading database ... 181674 files and directories currently installed.)
Preparing to unpack .../pound_2.7f-0ubuntu1_amd64.deb ...