Nexion
I looked at the Nexion site. Looks interesting. (There is a $199 one-time setup fee, if I read it correctly, before you can pay $39/month for the system access.)
But, for those of you who really do a lot of travel (and who are very sophisticated with business) there is an option to pay $300 per month with full ticketing and you get 100% of the commissions. So if you spend at least $10,000 per month on travel, this might be worthwhile.