I've started development on Nostos, a ruby on rails application that automatically creates short records in Voyager for returnable items received in Illiad. This allows Voyager libraries to circulate Illiad returnables within Voyager's circulation module. This can already be done if libraries manually create the short records in Voyager, however it's tedious and best left to automation. That's what Nostos is for.
I've already created a working prototype that is in production at UMass Boston since the start of the Fall 2010 semester. It's a single PHP script that polls Illiad for loan transactions and creates a short record in Voyager using the SIP protocol. Nostos, however, will be written in Ruby on Rails, have an administrative interface, be well tested, and sustainable into the future (my PHP script was not).
Having Illiad returnables circulate in Voyager has been a boon for everyone at UMass Boston. Patrons can check a single account to check on the status of all their items on loan. Patrons are also sent courtesy, overdue, recall, and lost notifications that are consistent with other circulation transactions. Patrons will also accrue fines and fees, which will encourage timely returns.
Most importantly, very little additional staff time was required to achieve these results. In fact, I'd argue that integration of Voyager and Illiad saves you time. Nostos only makes it easier.
You can follow the development at Github: https://github.com/bricestacey/nostos.
I intend to develop Nostos using test driven development. I really want to make it work and be able to verify that it works in future. I'll be creating integrated tests with Cucumber and unit testing with RSpec.
Let me know what you think of the project in the comments. I'd like to discuss with anyone interested.