accepting xml feeds system for vacation rental listings

We need a system that will read xml feeds from various partners and save them into our database. This is for a vacation rentals site. We will define all fields for our partners, some will be optional, others will be required. I will give you the xml feed list once the bid is accepted. There are about 90 fields that we collect. The feed system will also need to download images for each listing and save that into our filesystem and into a mysql table with dimensions, file extension, etc. The feed system should be able to detect changes in a listing provided by a partner and modify it in our database. It should be able to detect deletions as well as new additions without re-importing all listings every time. A sample feed would look like: . . .