I took the MikroTik class in Houston last year, one of the instructors helped me set up IPsec across two natting routers both with their own gateways and seperate ISPs. basicly an IPSec VPN without L2TP or PPTP.
It takes setting up the peers, and a couple of simple firewall rules on both of the routers and you are up..
This link currently supports 80 desktop users in a remote site from my data center 20 miles away across two T1 lines. (Thank you Terminal services.)
I would love to publish how it is done, but, that would not be fair to him. If he wants to publish it than GREAT, but for anyone who wants to "hire him"
Drop me a line at:
sales@software-routers.com and I will get you in touch with him. (I cant give out his email directly, he will contact you)
Craig