I think most of Alan's concerns about integratability with other proposals, acceptability by USG, nature of PRT etc have been addressed by multiple people.
What remains un-answered are Alan's concerns about (i) Contract Co becoming a target for litigation; (ii) source of funding of Contract Co; (iii) jurisdiction of Contract Co; and (iv) accountability of Contract Co.
I agree that these are substantial concerns.
The Contract Co can be the subject of litigation for multiple reasons including wrongful termination of a IANA contract; or any cause of action related to a failed bid for a IANA contract. It can also be reasonable to assume that Contract Co will be made a party to all cases that are against ICANN in the future. For example, a case similar to the recent 'Iran/Iraq ccTLD as attachable property' will definitely make Contract Co a respondent along with ICANN.
Therefore, Contract Co will need a substantial litigation war chest. There will also be substantial costs involved in contract drafting; negotiation; preparation of RFPs etc. This needs to be addressed. Greg suggested the possibility of a litigation indemnification mechanism. A mechanism to deal with unforeseen non-litigation expenses should also be explored.
@Allan & Olivier: What accountability mechanisms do you suggest should be built into the Contract Co by-laws?