Is there an HAProxy virtual machine (any OS) with HAProxy installed but not configured (or configured and I'll just reconfigure)?
There isn't (to my knowledge anyway) however it's trivial to install on most distributions. Create a small VM with your distribution of choice and then install the HAProxy package. On Debian based distros it's as easy as
apt-get install haproxy. For CentOS/RHEL, you'll need to add the EPEL repo, and then
yum install haproxy