Check Persumma out of Boston, MA. It's a JV between an insurance company and an e 401k start up, been around about a year? Ted Benna is involved, I think he sits on the board. The product is 100% brokerage window.
State Street is pricey. Schwab's costs are reasonable, but they want to do the servicing and run all of the assets. They don't play well with others, so incorporating them into an exisiting program as a new option/offering is going to be tough.
New player is T D Waterhouse, they've been making strides but I'm not sure how much is real and how much is still vaporware.
Most of the discount brokers eTrade, Brown etc have some type of offering as well as most of the full blown wirehouses.